Showing papers on "Middle cerebral artery published in 1976"

Cerebral Protection by Barbiturate Anesthesia: Use After Middle Cerebral Artery Occlusion in Java Monkeys

Abstract: • Regional cerebral ischemia was produced in 18 Java monkeys by permanent middle cerebral artery (MCA) occlusion. All monkeys were thereafter paralyzed (pancuronium bromide, 0.05 mg/kg/hr) and sedated (diazepam, 0.1 mg/kg/hr) for a 48-hour period. Thirty minutes after MCA occlusion, pentobarbital sodium anesthesia was induced in nine of the monkeys (14 mg/kg) and maintained for 48 hours (7 mg/kg every two hours), with continuous supportive care. After 48 hours, all drugs were discontinued; the monkeys were observed for five days, and then killed. Seven of the control monkeys developed a cerebral infarction, three did not survive past the 48 hours of intensive care, and the other four had a notable neurologic deficit. All pentobarbital monkeys survived the seven days, but four had a cerebral infarction and two of these had a notable neurologic deficit. These differences were statistically significant.

Cortical neuronal function during ischemia. Effects of occlusion of one middle cerebral artery on single-unit activity in cats.

Abstract: • To assess the effects of ischemia on neuronal function, the action potentials of 261 individual cortical neurons were recorded extracellularly and related to regional cerebral blood flow (CBF) measured by hydrogen clearance in 19 cats, seven of which had the left middle cerebral artery occluded during a recording. The onset of ischemia could be associated with transient increases of activity, including "seizure discharges," as well as cessation of activity. No activity was noted at CBF less than 0.18 ml/gm/min; at higher (but ischemic) values for CBF, abnormal patterns of activity frequently were recorded. One neuron recovered function after cessation in association with an increase of CBF, indicating a potential for the restoration of function of ischemic neurons by effective therapeutic measures.

Radiologic Anatomy of the Brain

Abstract: 1. Cerebral Hemisphere.- 1. Fissures and Sulci (G. S.).- I. Anatomic Study of the Fissures and Sulci of the External Surface of the Cerebral Hemisphere.- 1. Principal or Interlobar Fissures.- 2. Sulci of the External Surface.- a) Sulci of the Frontal Lobe.- b) Sulci of the Parietal Lobe.- c) Sulci of the Occipital Lobe.- d) Sulci of the Temporal Lobe.- II. Anatomic Study of the Fissures and Sulci of the Internal Surface of the Cerebral Hemisphere.- 1. Fissures of the Internal Surface.- 2. Sulci of the Internal Surface.- III. Anatomic Study of the Fissures and Sulci of the Inferior Surface of the Cerebral Hemisphere.- 1. Fissure of the Inferior Surface-Sylvian Fissure.- 2. Sulci of the Inferior Surface.- a) Sulci of the Orbital Surface of the Frontal Lobe.- b) Sulci of the Inferior Surface of the Temporal and Occipital Lobes.- IV. Radiologic Study of Fissures and Sulci.- 2. Lateral Ventricles (G. S.).- I. Anatomic Study of the Lateral Ventricles.- 1. Frontal Horn of the Lateral Ventricle.- 2. Body of the Lateral Ventricle.- 3. Atrium of the Lateral Ventricle.- 4. Occipital Horn of the Lateral Ventricle.- 5. Temporal Horn of the Lateral Ventricle.- II. Radiologic Study of the Lateral Ventricles.- 1. Frontal Horn of the Lateral Ventricle.- 2. Body of the Lateral Ventricle.- 3. Atrium of the Lateral Ventricle.- 4. Occipital Horn of the Lateral Ventricle.- 5. Temporal Horn of the Lateral Ventricle.- 3. Cortical Arteries (G. S.).- A. Anterior Cerebral Artery.- I. Anatomic Study of the Anterior Cerebral Artery.- Branches of the Anterior Cerebral Artery.- a) Branch to the Orbital Surface of the Frontal Lobe.- b) Branches to the Internal Surface of the Frontal Lobe.- c) Branch to the Paracentral Lobule.- d) Branches to the Internal Aspect of the Parietal Lobe.- e) Branches to the Corpus Callosum.- II. Radiologic Study of the Anterior Cerebral Artery.- B. Middle Cerebral Artery.- I. Anatomic Study of the Middle Cerebral Artery.- 1. Patterns of Division of the Middle Cerebral Artery within the Sylvian Fissure.- 2. Frontal Branches of the Middle Cerebral Artery.- 3. Parietal Branches of the Middle Cerebral Artery.- 4. Temporal and Temporo-Occipital Branches of the Middle Cerebral Artery.- 5. Insular Branches.- II. Radiologic Study of the Middle Cerebral Artery.- C. Anterior Choroidal Artery.- I. Anatomic Study of the Anterior Choroidal Artery.- II. Radiologic Study of the Anterior Choroidal Artery.- D. Posterior Cerebral Artery.- I. Anatomic Study of the Posterior Cerebral Artery.- II. Radiologic Study of the Posterior Cerebral Artery.- 4. Basal Cerebral Vein (Y. P. H.).- A. Normal Anatomy.- I. First Segment of the Basal Cerebral Vein and Its Tributaries.- 1. Deep Middle Cerebral Vein.- 2. Inferior Striate Veins.- 3. Olfactory Vein.- 4. Fronto-Orbital Veins.- 5. Anterior Cerebral and Pericallosal Veins.- 6. Veinlets from the Optic Chiasm, Optic Tract, and Adjacent Structures.- II. Second Segment of the Basal Cerebral Vein and Its Tributaries>.- 1. Peduncular Vein.- 2. Inferior Ventricular Vein.- III. Third Segment of the Basal Cerebral Vein and Its Tributaries.- 1. Lateral Mesencephalic Vein.- 2. Lateral Atrial Vein.- 3. Medial Temporal and Occipitotemporal Cortical Veins.- 4. Posterior Longitudinal Hippocampal Vein.- 5. Posterior Thalamic Veins.- B. Anatomic Variations.- 2. Mesencephalic Region, Diencephalic Region, and Basal Ganglia.- 1. Third Ventricle and Suprasellar Cisterns (G. S.).- I. Anatomic Study of the Third Ventricle and Suprasellar Cisterns.- 1. Third Ventricle.- 2. Suprasellar Cisterns.- II. Radiologic Study of the Third Ventricle and Suprasellar Cisterns.- 2. Aqueduct of Sylvius (G. S.).- I. Anatomic Study of the Aqueduct of Sylvius.- II. Radiologic Study of the Aqueduct of Sylvius.- 3. Arteries of the Basal Ganglia and the Posterior Choroidal Arteries (G. S.).- I. Anatomic Study of the Perforating Arteries of the Basal Ganglia and of the Posterior Choroidal Arteries.- 1. Perforating Branches of the Carotid System.- a) Perforating Branches of the Anterior Cerebral Artery.- b) Perforating Branches of the Middle Cerebral Artery.- c) Perforating Branches of the Anterior Choroidal Artery.- 2. Perforating Branches of the Vertebrobasilar System.- a) Arteries to the Inferior Surface of the Thalamus.- b) Arteries to the Posterior Surface of the Thalamus.- c) Arteries to the Superior Surface of the Thalamus.- II. Radiologic Study of the Perforating Arteries of the Basal Ganglia and of the Posterior Choroidal Arteries.- 4. Deep Cerebral Veins (Y. P. H.).- A. Internal Cerebral and Great Cerebral Veins.- B. Subependymal Veins of the Lateral Ventricle.- I. Medial Group of theSubependymal Veins.- 1. Septal Vein.- 2. Posterior Septal Vein.- 3. Medial Atrial Vein.- 4. Transverse Hippocampal Subependymal Veins.- II. Lateral Group of the Subependymal Veins.- 1. Thalamostriate Vein.- 2. Direct Lateral Vein.- 3. Inferior Ventricular Vein.- C. Choroidal Veins of the Lateral Ventricle.- D. Veins of the White Matter of the Cerebral Hemisphere-Medullary Veins.- E. Veins of the Grey Matter of the Cerebral Hemisphere.- 3. Posterior Fossa.- 1. Fourth Ventricle and Cisterns of the Posterior Fossa (G. S.).- I. Anatomic Study of the Fourth Ventricle.- 1. Floor of the Fourth Ventricle.- 2. Roof of the Fourth Ventricle t2.- II. Anatomic Study of the Posterior Fossa Cisterns.- 1. Cisterns Anterior to the Brainstem.- a) Medullary Cistern.- b) Pontine Cistern.- c) Cerebellopontine Angle Cistern.- 2. Cistern Posterior to the Medulla and Below the Inferior Vermis-Cisterna Magna.- 3. Cisterns Posterior to the Tectum and Superior to the Cerebellum.- 4. Cisterns Around the Cerebral Peduncles.- III. Radiologic Study of Posterior Fossa, Fourth Ventricle and Cisterns of the Posterior Fossa.- 2. Arteries of the Vertebrobasilar System (G. S.).- I. Anatomic Study of the Arteries of the Vertebrobasilar System.- 1. Intracranial Segment of the Vertebral Artery.- 2. Basilar Trunk.- 3. Arteries of the Brainstem.- a) Arteries of the Medulla.- b) Arteries of the Pons.- c) Arteries of the Cerebral Peduncles.- 4. Arteries of the Cerebellum.- a) Superior Cerebellar Artery-SCA.- b) Anterior Inferior Cerebellar Artery-AICA.- c) Posterior Inferior Cerebellar Artery-PICA.- II. Radiologic Study of the Arteries of the Vertebrobasilar System.- 1. Basilar Trunk and Its Branches.- 2. Anterior. Inferior Cerebellar Artery-AICA.- 3. Superior Cerebellar Artery-SCA.- 3. Veins of the Posterior Fossa (Y. P. H.).- I. Superior or Galenic Draining Group.- 1. Mesencephalic Tributaries.- 2. Cerebellar Tributaries.- II. Anterior or Petrosal Draining Group.- 1. Tributaries Related to the Anterior Aspect of the Brain Stem.- 2. Tributaries Related to the Wing of the Precentral Cerebellar Fissure.- 3. Tributaries Related to the Posterolateral Fissure.- 4. Tributaries Related to the Cerebellomedullary Fissure.- 5. Tributaries Related to the Cerebellar Hemisphere.- III. Posterior or Tentorial Draining Group.- IV. Intercommunications Among the Superior, Anterior and Posterior Draining Groups and Between the Supra- and Infratentorial Veins.- V. Circulation Times of Veins of the Posterior Fossa.- References.

Bypass surgery for vascular disease of the carotid system.

Abstract: A series of 58 operations on 56 patients, in whom a branch of the superficial temporal artery was anastomosed to a branch of the middle cerebral artery (STA-MCA bypass or Yasargil procedure), is reviewed. These operations were performed chiefly for occlussions or for inaccessible stenotic lesions of the internal carotid or middle cerebral arteries. Patency in eight patients operated on from April 1971 through November 1973 was low (25%). Patency in patients operated on since July 1974 has been high (95%). There have been no deaths and no major ischemic strokes attributable to the surgery. The rationale for this procedure is considered in relationship to the anatomy and physiology of the cerebral circulation and the pathogenesis of syndromes of cerebral ischemia. The operation appears to have a low morbidity in good-risk patients. The role of this operation in managing common manifestations of cerebral vascular disease such as focal transient cerebral ischemic attacks (TIAs) and amaurosis fugax, although not fully established, appears encouraging. The procedure seems useful for orthostatic cerebral ischemia caused by multiple occlusions of major extracranial (and intracranial) vessels and, occasionally, for progressing strokes related to internal carotid artery occlusion, both of which are relatively uncommon manifestations of cerebral vascular occlusive disease. It may have application in the rare "slow stroke." The procedure is probably of limited value, if any, in the management of large completed infarcts but may be indicated in selected patients with small infarctions who have preserved most of their cerebral function and who have had evidence of subsequent focal ischemic events. The procedure is useful for bypassing giant aneurysms or basofrontal tumors invading major vessels. It may have a role in the management of fibromuscular disease of the internal carotid artery.

Recovery of the cortical evoked response following temporary middle cerebral artery occlusion in baboons: relation to local blood flow and PO2.

Abstract: The degree of recovery of the somatosensory cortical evoked response following a period (15 to 65 minutes) of partial ischemia, produced by temporary occlusion of the middle cerebral artery (MCA), was assessed in baboons and related to the local tissue blood flow and PO2 before, during and after the occlusion. Flow was measured using the technique of two-minute hydrogen clearance. Failure of complete recovery of the evoked response was associated with significantly greater depths of ischemia and tissue hypoxia during occlusion, and with significantly greater and persisting tissue hypoxia after occlusion, than complete recovery. Complete recovery of the evoked response also was associated with tissue hyperoxia after occlusion. The reduced postocclusive PO2 levels associated with incomplete recovery of the evoked response suggest that reduced perfusion during ischemia was sufficiently severe to cause some degree of irreversible anoxic damage. The effect of a brief (three to ten minutes) period of ventilation with air (instead of oxygen) under such low-flow conditions was to depress the evoked response significantly further; normally perfused brain, however, was unaffected by this procedure. This finding has clinical implications in regard to normobaric oxygen therapy.

Microcirculatory Obstruction in Focal Cerebral Ischemia: An Electron Microscopic Investigation in Monkeys

Abstract: The fine structure of the microvasculature in areas of focal cerebral ischemia was studied in squirrel monkeys and the changes in areas of impaired and unimpaired microvascular filling, as defined by carbon perfusion, were compared. Microcirculatory obstruction became evident three hours following middle cerebral artery (MCA) occlusion and appeared to be partly the result of compression of capillaries by perivascular glial swelling and developing cerebral edema. Slight endothelial swelling was a common finding. Intraluminal membrane-bound bodies were occasionally identified but they did not appear to be producing significant obstruction. The tight endothelial junctions remained intact and there was no evidence of accelerated micropinocytosis. Severe neuronal injury frequently preceded the development of the microvascular obstruction and was more widespread than the zones of impaired perfusion.

Fibromuscular dysplasia and multiple dissecting aneurysms of intracranial arteries. A further cause of Moyamoya syndrome.

Abstract: A 16-year-old boy, who had sudden left-sided hemiplegia, died two weeks following onset of symptoms. A right carotid angiogram showed stenosis at the termination of the internal carotid artery. The middle cerebral artery had a beaded appearance and some of its branches were occluded. A basal "moyamoya" syndrome and transdural anastomoses were present. At autopsy, multiple intracranial dissecting aneurysms were found. Arteries of the body displayed fibromuscular dysplasia (FMD). The relevance of dysplastic changes of intracranial arteries and the relationship to moyamoya syndrome are discussed.

Dexamethasone and DMSO in experimental transorbital cerebral infarction.

Abstract: Twenty rhesus monkeys were used to evaluate the effects of dexamethasone and dimethyl sulfoxide (DMSO) following experimental occlusion of the middle cerebral artery (MCA) for 17 hours. Animals were initially treated after four hours while the MCA remained occluded and a series of tests was used to evaluate the neurological and cerebral status of each monkey for seven days. The results show that the gross, microscopic and angiographical picture of dexamethasone and no-treatment controls was practically identical. In contrast, DMSO-treated monkeys showed significant protection from the severe neurological deficits seen in the other groups. It is concluded that DMSO has a positive effect in reducing the neurological deficits seen in this model and may be potentially useful in clinical emoblic stroke.

Primate Model of Cerebral Hematoma

Abstract: Using specific anesthetic agents, permanent segmental occlusion of the proximal middle cerebral artery (MCA) causes ischemic infarction limited to the putamen and other deep hemispheral structures in primates. Using this model, 25 rhesus monkeys were subjected to acute arterial hypertension before, during and up to 5 days after onset of MCA occlusion in order to reevaluate the possible role of the ischemic process in pathogenesis of cerebral hemorrhage. Norepinephrine infusion induced prompt rapid rise in mean arterial pressure (MAP) and intracranial pressure (ICP) limited to the duration of infusion. This procedure produced acute ischemic lesions which were totally bland but topographically more extensive than untreated controls; in chronic lesions, however, deep nuclear masses showed hemorrhagic infarction. Animals given 5% CO2 air had slowly progressive elevation in ICP and MAP. Acute specimens showed intact, widely-dilan hypercarbia was induced 5 days after MCA occlusion, animals developed intracerebral hematoma involving putamen, external capsule and claustrum, occasionally dissecting through to ipsilateral ventricle. In acute cerebral ischemia, elevated MAP produced only quantiative changes in lesion size. In the vasoproliferative stages of mature infarction, MAP elevation induced by a cerebral vasoconstrictor caused hemorrhagic infarctions while cerebral vasodilation caused intracerebral hematomas.

Fibromuscular dysplasia and multiple dissecting aneurysms of intracranial arteries. A further cause of Moyamoya syndrome.

Abstract: A 16-year-old boy, who had sudden left-sided hemiplegia, died two weeks following onset of symptoms. A right carotid angiogram showed stenosis at the termination of the internal carotid artery. The middle cerebral artery had a beaded appearance and some of its branches were occluded. A basal "moyamoya" syndrome and transdural anastomoses were present. At autopsy, multiple intracranial dissecting aneurysms were found. Arteries of the body displayed fibromuscular dysplasia (FMD). The relevance of dysplastic changes of intracranial arteries and the relationship to moyamoya syndrome are discussed.

Reversibility of the chronic post-stroke state.

Abstract: Forty patients with cerebral infarction associated with occlusion of the internal carotid artery (ICA) or the middle cerebral artery (MCA) were treated with hyperbaric oxygenation (HO). EEG analyses were performed regularly in order to assess the course of the cerebral lesion. Patients in an early post-stroke stage (III B) and patients in a chronic post-stroke stage (IV) had the changes in EEG analysis and neurological distributed evenly between these two groups.

Effect of hypocapnia, hypercapnia, and blood pressure on NADH fluorescence, electrical activity, and blood flow in normal and partially ischemic monkey cortex.

Abstract: — Nicotinamide adenine dinucleotide fluorescence, cortical reflectance, cortical blood flow, and electroencephalograms were recorded from squirrel monkey brains before, during, and after focal transient cerebral ischemia produced by the temporary clipping of the middle cerebral artery. After release of the occluding clip, the monkeys were followed through an N2-breathing cycle and then to death from anoxia. The effects of controlled variations in arterial carbon dioxide tensions (Paco2) and mean arterial blood pressures (MABP) were investigated in normal and in ischemic brain. In normal brain, with preserved autoregulation, NADH fluorescence was constant through a wide range in Paco2, MABP, and cortical blood flow. In ischemic brain, NADH levels increased, correlated closely with decreased cortical blood flow and EEG abnormalities, and became dependent on MABP. Artifacts in fluorescent measurements were reduced by: monochromators for excitation, emission, and reflected light; low intensity vertical excitation energy and high sensitivity recording instrumentation; and a small avascular (123 μm) field.

Middle cerebral artery embolectomy. Case report.

Abstract: ✓ A patient who developed an embolic occlusion of the right middle cerebral artery while undergoing a cerebral arteriogram was successfully operated on by removal of the embolus under the surgical microscope. Early postoperative cerebrovascular spasm was a factor in the transient deterioration of the patient's neurological condition. When the patient was last seen 2 ½ months after surgery she was almost intact neurologically with only a mild right parietal dysfunction but with total resolution of the left hemiplegia. The literature is reviewed.

Spontaneous cerebral revascularization in a patient with STA-MCA anastomosis. Case report.

Abstract: ✓ The authors report a case with spontaneous revascularization of the brain after surgical anastomosis of the superficial temporal artery to the middle cerebral artery.

Acute ultrastructural changes in the middle cerebral artery due to the injury and ischemia of surgical clamping.

Abstract: Ultrastructural changes in the zone of clamping of the middle cerebral artery of the squirrel monkey are described after application of a surgical clip. The experimental model utilized has been widely applied to the study of cerebral ischemia and possibly has relevance to clamps applied to the cerebral vessels during neurosurgical treatment of patients with cerebrovascular disorders. The earliest changes within the arterial wall were found in the smooth muscle (media) and accompanying fasciculi of nerves. Changes within the nerve bundles were sufficiently advances following 4 hours of vascular clipping to suggest temporary or permanent impairment of neurogenic innervation of the cerebral vessels distal to the trunk of the vessel clipped.

Experimental middle cerebral artery microsurgical embolectomy.

Abstract: The canine middle cerebral has been embolized using the method of Molinari. Microsurgical embolectomies were done at two hours and six hours post-embolism. Animals done at two hours remained virtually intact neurologically, and hence fared better than control dogs whose embolus remained in place. Animals done six hours post embolism had increased neurologic morbidity and mortality as compared to the controls. Pathologic study revealed hemorrhagic infarctions in 50% of the animals done six hours post embolism.

Color functional images of the cerebral blood flow.

Abstract: Functional gamma imaging, in color, was established for regional cerebral blood flow (rCBF) using 133Xe. During 10 min after intracarotid injection of 133Xe in saline, 60 picture frames of the 133Xe clearance curve for the entire hemisphere were obtained. After nine-point smoothing, the rCBF for each of the 4,096 picture elements was calculated by two methods: the half-time method and the height-over-area method. Both the 133Xe clearance half-times and the calculated CBF values were displayed, using 13 steps of color, as functional CBF images of the brain. Images of peak count and total count were also displayed on the same frame of the color television. Forty-six studies, performed on 37 patients with various cerebral disorders, were divided into two types: diffuse and focal. In the diffuse type, a decrease in CBF was noted in cases of normal-pressure hydrocephalus; successful ventriculoperitoneal shunt operations were followed by recovery of CBF. Occlusion of the middle cerebral artery showed up as a wedge-shaped area of decreased CBF, even when the conventional brain scan looked normal. Increased perfusion to a tumor was frequently associated with decreased CBF in the rest of the lateral hemisphere; such a decrease could be improved by surgical removal of the tumor.

Comparison of Regional Cerebral Blood Flow and Computerized Tomography in Patients with Cerebrovascular Disease and Brain Tumors

Abstract: Since the introduction of CT as a noninvasive technique for brain imaging, several reports have discussed its merits as opposed to conventional neuroradiologic diagnostic procedures. To our knowledge, however, no data have been presented until now, that have included into comparative methodological analysis the technique of regional cerebral blood flow (rCBF) as well. It is the purpose of this study to comparer CBF and CT in patients presenting with cerebrovascular disease and in a smaller group of patients with brain tumors.

H+, CO2, Prostaglandins and Cerebrovascular Smooth Muscle

Abstract: It remains unproven that the effect of hypercapnia on cerebral blood flow is entirely attributable to the associated change in ECF pH evoked by the rapid diffusion of carbon dioxide across the blood-brain barrier. This effect of hypercapnia on CBF can be blocked without any change in cerebral oxygen consumption by indomethacin, an inhibitor of prostaglandin synthesis (7). The CO2 response is also dependent on the resting level of cerebral oxygen consumption (4). We have suggested that an endogenous prostaglandin (or thromboxane) might provide a link between hypercapnia and cerebral vasodilatation. These considerations prompted us to quantify the effects of CO2 and ECF pH separately on a segment of the cerebrovascular tree, the middle cerebral artery (MCA), in vitro.

Intracranial neurosurgical treatment of occlusive cerebrovascular disease.

Abstract: Anastomosis of the extracranial superficial temporal artery to the intracranial middle cerebral artery offers an additional source of blood to the cerebral circulation in patients with transient ischemic episodes. Fourteen cases are reported. Two representative cases with three anastomoses demonstrate the use of this technique in occlusion of the internal carotid artery, occlusion of the middle cerebral artery and stenosis of the middle cerebral artery. Indications and contraindications of the procedure are discussed.

Acute Hemiplegia in Children Complicating Upper Respiratory Infections Report of Three Cases with Angiographic Findings

Abstract: Three children presented with acute onset of hemiplegia following an upper respiratory infection. Angiography revealed irregularities, beading, and slow flow of a peripheral branch of a middle cerebral artery. In addition, one child had narrowing of the cervical segment of the internal carotid artery. An inflammatory arteritis of the cervical internal carotid artery is presumably the site of the formation of cerebral emboli.

[Angiographical findings in extra-intracranial anastomoses (author's transl)].

Abstract: A microsurgical anastomosis between the superficial temporal artery and a cortical branch of the middle cerebral artery was carried out in 11 cases with internal carotid occlusion. This treatment was attempted following angiography of the intra- and extracranial cerebral arteries. After the microsurgical procedure for creating an extra-intracranial arterial anastomosis selective angiography of the homolateral external carotid circulation was performed. The analyses of the serial arteriograms showed, that a) a considerable blood supply from the external carotid circulation through the additional collateral pathway to the territory of the middle cerebral artery is possible, b) the extent of the area of the middle cerebral artery supplied by the superficial temporal artery is not only dependant upon a pressure gradient between the external carotid and the middle cerebral artery circulation, but also by the different anatomical variations of the middle cerebral artery.

Variation of the Circle of Willis Related to the Pathogenesis of Cerebral Aneurysm

Abstract: Arterial bifurcations in the circle of Willis were observed three-dimensionally in 44 cases of cerebral aneurysm and 45 control cases. Variations of the circle of Willis were also studied in relation to cerebral aneurysm. The following results were obtained : 1. Aneurysm always occurred at the apex of the cerebral arterial bifurcation where axial flow in the parent artery immediately proximal to the aneurysm was assumed to impinge. 2. A statistically valid correlation was found between cerebral aneurysm and anterior middle cerebral artery. A statistically valid correlation was also noted between the external diameter of the parent arteries and the side of aneurysms in 19 anterior communicating aneurysms and 5 posterior communicating aneurysms. When the proximal portion of the anterior cerebral artery or when the posterior communicating artery was thicker than the contralateral one, the aneurysm tended to occur on the thicker side. 3. One aneurysm developed on a dilated feeding artery of an associated cerebral arterio-venous malformation. Another one developed at the proximal branching point from an associated accessory middle cerebral artery. These results show the preponderence of the occurrence of cerebral aneurysm at sites where blood flow is relatively abundant because of some variation in the form of the circle of Willis. They also suggest that hemodynamic stress plays an important role in the pathogenesis of cerebral aneurysm.

Results of Serial Scintigraphy with 99mTC-Pertechnetate in Comparison with Angiography and Computerized Tomography in Cerebrovascular Diseases

Abstract: The validity of cerebral serial scintigraphy (CSS) with 99mTc-pertechnetate in the evaluation of cerebral vascular diseases has been assessed by many authors (ROSLER et al. , 1970; STRAUSS et al. , 1973; TYSON et al. , 1974). The noninvasive sequential scintigraphy (stage I of CSS), i.e., the fast series of Polaroid photos taken immediately after the appearance of 99mTc in the carotid arteries, is a method comparable to the invasive contrast carotid angiography (CCA). It is obvious that this cerebral radionuclide angiography (CRA) cannot image arteries and their arborization in the same detailed way as CCA. However, areas supplied by major cerebral arteries can be examined by CRA with respect to the symmetry of regional blood flow, to the extent of unperfused regions, and to increased blood flow as far as aneurysms (GOODMAN and HAYES, 1974), angiomas, and other tumors are concerned (BULL et al. , 1976). It is known that CT procedures do not as yet include a correlative method to the noninvasive CRA as far as blood-flow dynamics are concerned. Findings by contrast enhancement in CT correspond with the findings of stage II (blood content of the vascular pool) and those of stage III (leaking of radio nuclides across the blood-brain barrier) of CSS, as was recently shown by GADO et al. (1975).