Factors affecting measurements in computed-tomography-guided stereotactic procedures.
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Humans↗
Biomedical subjects
M Dujovny
Publications and source records attributed to M Dujovny.
Microanatomy of the posterior communicating artery.
Fifty unfixed cerebral hemispheres were injected with polyester resin and dissected under the operating microscope to show the anatomy of the posterior communicating artery (PCoA). There was a single PCoA in every hemisphere. Eleven (22%) were of fetal origin, and 17 (34%) were hypoplastic. Infundibular dilatations were found in 5 (10%) of the arteries. The outer diameter (OD) of the PCoA at its origin was 1.5 +/- 0.8 mm on the right and 1.6 +/- 0.6 mm on the left. At the junction of the PCoA with the P1 segment of the posterior cerebral artery, the PCoA had an OD of 1.4 +/- 0.7 mm on the right side and 1.6 +/- 0.6 mm on the left. The total length of the PCoA was 12.7 +/- 3.2 mm on the right and 12.5 +/- 1.7 mm on the left side. PCoA branches originated from the superior (36%) or lateral (64%) surface of the PCoA and coursed superiorly, posteriorly, or laterally. These vessels supplied the paramedian perforated substance (21%), the tuber cinereum (16.8%), the sulcus between the optic tract and the tuber cinereum (14.4%), the circuminfundibular anastomosis (11.5%), the mamillary bodies (8.4%), the sulcus between the optic tract and the cerebral peduncles (7.6%), and the cerebral peduncles (5.7%). The largest and most constant branch of the PCoA was the premamillary artery. The number and size of the branches from the PCoA were independent of the size of the parent artery.
Adult↗
Intramembranous cytochemistry: a new morphological technique for studying cholesterol in the astrocyte plasma membrane of ischemic brain cells.
The distribution of cholesterol in the astrocytic plasma membranes of normal and ischemic caudate nucleus in the cat was investigated with the polyene antibiotic, filipin, a morphological probe for membrane cholesterol domains in freeze-fracture tissue replicas. After filipin incubation of prefixed vibratome slices, filipin-cholesterol complexes appeared as 20 to 30 nm protuberances and pits on P- and E-faces of the replicas. Distinct patterns of filipin-cholesterol complexes were found on nonischemic and ischemic astrocyte membranes. The filipin-treated specimens showed an 80% decrease in astroglial plasmalemma of cholesterol 1 hour after cerebral ischemia.
Animals↗
Multiplanar CT-guided stereotaxis and 125I interstitial radiotherapy. Image-guided tumor volume assessment, planning, dosimetric calculations, stereotactic biopsy and implantation of removable catheters.
A method using Multiplanar CT-guided stereotactic biopsy and high-dose 125I interstitial radiotherapy in patients with malignant nonresectable or recurrent brain tumors is presented. Optimal interstitial radiotherapy requires careful preoperative planning, computer-assisted dosimetry, CT-guided stereotactic biopsy and implantation of catheters that will be loaded with 125I seeds. A method is presented by which the isodose curve distribution is adjusted to the tumor size, volume and axis, allowing treatment of the imaged and histologically determined border of the tumor with 60 Gy at a dose rate of 40 rad/h.
Biopsy↗
Ultrasonic features of two cases of spinal cord hemangioblastoma.
Two patients with proven intramedullary spinal cord hemangioblastomas were examined with intraoperative ultrasound. The ultrasonic features of a hyperechoic intramedullary mass accompanied by nearby cysts and, in one case, by a syrinx correspond with well-known pathological and computed tomographic descriptions of these tumors. Ultrasonic guidance enabled the surgeon to identify the exact location of the tumors and to proceed with the surgery, limiting the dissection to the area detected. The ultrasound also revealed cysts associated with the tumors, thus providing valuable information to guide the progress of surgery.
Adolescent↗
Microanatomy of the anterior cerebral artery.
The microanatomic features of the anterior cerebral artery were studied in 30 unfixed human brains which were injected with tinted polyester resin via cannulation of the internal carotid arteries under microscopic dissection. The outer diameter, length, and number of perforating branches were measured for each of the following vessels: anterior cerebral artery (proximal A1 segment, distal A2 segment), anterior communicating artery, and recurrent artery of Heubner. The perforating branches of the proximal segment of the anterior cerebral artery penetrated the brain at the anterior perforated substance, lateral chiasm, and optic tracts. The perforating branches of the anterior communicating artery penetrated the brain at the lamina terminalis, anterior perforated substance, and medial chiasm. The first 5 mm of the distal anterior cerebral artery (A2) had perforating branches penetrating the brain at the gyrus rectus and olfactory sulcus. The recurrent artery of Heubner originated from the A2 segment of the anterior cerebral artery in 57% of the cases, from the anterior cerebral artery-anterior communicating artery junction in 35%, and from the A1 segment in 8%. The depth of the interhemispheric fissure at the genu was 36.0 +/- 0.5 mm and at the midbody of the corpus callosum, 35.0 +/- 0.5 mm. Extension of the dissection to approach the anterior communicating artery from the genu of the corpus callosum using the anterior interhemispheric route was an additional 31.7 +/- 0.7 mm. The callosal arterial supply from the anterior cerebral artery showed short callosal branches in all brain specimens and long callosal vessels in 10% of the specimens.
Cerebral Arteries↗
Anterior cerebral artery reconstruction.
Anterior cerebral artery end-to-end, end-to-side, and side-to-side anastomoses and grafting procedures including bypass and interposition using segments of the posterior cerebral artery harvested from the same specimen were performed. The reconstruction procedures were accomplished experimentally with the A1 and A2 segments of the anterior cerebral artery, the recurrent artery of Heubner (RAH), and the orbitofrontal and frontopolar arteries in end-to-end or end-to-side anastomosis to the A1 segment. Side-to-side anastomoses between both A2 or A3 segments were completed without difficulty. We utilized the anatomical and experimental reconstruction data in the performance of three surgical procedures for aneurysms in this area. An A1 to A2 end-to-end anastomosis, an A2 to A2 end-to-side anastomosis, and an end-to-end anastomosis of the RAh were performed with no technical difficulties or complications. This study shows the feasibility of these microvascular reconstruction procedures in the anterobasal part of the interhemisphere, where cerebral aneurysms frequently develop.
Adult↗
Surgical correction of lesions affecting the second portion of the vertebral artery.
Substantial controversy has surrounded the diagnosis and management of vertebrobasilar ischemic events, with no consensus on the value of medical or surgical treatment of patients symptomatic with brain stem ischemia who have angiographically proven vertebral artery lesions. This report presents our experience with the surgical treatment of 12 of 88 patients with angiographically verified lesions in the vertebral artery who were symptomatic for 1 to 12 months before their evaluation. None experienced symptomatic relief with antiplatelet agents, nor did the administration of anticoagulants in 4 of the patients provide any benefit. The lesions included bilateral vertebral artery occlusion with distal reconstitution through muscular collaterals in 6 patients, unilateral vertebral artery hypoplasia with contralateral long-tailed lesions from the vertebral artery origin to C-5 in 3 patients, and severe bilateral vertebral artery origin lesions extending beyond the C-5 level in 3 patients. A vertebral endarterectomy and vertebral-carotid transposition in the second portion of the artery were successfully used to reestablish flow and obtain symptomatic relief in 10 of the 12 cases; 1 of these procedures had to be redone because of a persistent stenosis at C-4. Another patient had a saphenous vein graft from the common carotid to the vertebral artery at C-5. The remaining patient had an anastomosis of the distal external carotid to the vertebral artery at C-3, but this failed and an anastomosis of the occipital artery to the anterior inferior cerebellar artery had to be completed to reestablish flow.(ABSTRACT TRUNCATED AT 250 WORDS)
Aged↗
Microvascular anatomy of the interpeduncular fossa.
An understanding of the microvascular anatomy of the midbrain and posterior diencephalon is essential in the surgical management of lesions in that region. A description of the arterial pattern of blood supply to these areas is the purpose of this study. Perforating branches originating from the last 5 mm of the basilar artery, from the initial 7 mm of both superior cerebellar arteries (SCA's), and from the initial segment (P1 segment) of the posterior cerebral artery were studied in 56 unfixed human cadaver brain hemispheres. The brains were injected with polyester resin. The perforating branches penetrated through a small space in the upper part of the interpeduncular fossa. The anterior two-thirds of this space was occupied by the posterior perforated substance (PPS), and the posterior one-third was the site of penetration of the branches that supply the inferior mesencephalon. The PPS was divided into anterior and posterior halves. The anterior half was perforated by the paramedian thalamic arteries (diameter 0.57 +/- 0.11 mm) while the superior paramedian mesencephalic arteries (diameter 0.20 +/- 0.06 mm) perforated the posterior half. The perforating arteries originated from a trunk exclusive to the anterior half in 30%, from a trunk supplying both halves in 57%, and from a trunk exclusive to the posterior half in 13% of specimens. There were 26 naturally occurring anastomoses between the perforating branches. The paramedian inferior mesencephalic arteries penetrating the posterior one-third of the upper part of the interpeduncular fossa arose from the P1 segment in 32% of the brains studied, from the proximal 7 mm of the SCA in 45%, and from the last 5 mm of the basilar artery in 23%.
Basilar Artery↗
Surgical anatomy of the arteries of the posterior fossa.
The development of revascularization for vertebrobasilar ischemic events has created a need to identify the best sites at which to perform bypass procedures. Since the occlusive process may selectively affect various levels of the vertebrobasilar tree, sites in different vessels must be used to reestablish flow distal to the area of occlusion. Twenty-seven unfixed human brains were obtained 4 to 8 hours post mortem, and the vertebrobasilar system was injected with polyester resin. Under a surgical microscope the outer diameter, length, and site of origin of major branches were recorded for the following arteries: vertebral, basilar, posterior inferior cerebellar (PICA), anterior inferior cerebellar (AICA), superior cerebellar (SCA), and posterior cerebral (PCA). The ideal sites for an anastomosis were identified as the pretonsillar segment of the PICA, the second portion of the AICA, the perimesencephalic segment of the SCA, and the perimesencephalic part of the PCA. Based on the anatomical observations reported here, these were the best sites because of their outer diameter, degree of mobility, least number of branches, and frequency of occurrence. Use of two of these arteries, however, may pose potential problems: although the PCA has an ideal outer diameter, it also has numerous branches to the brain stem in its most accessible site in the perimesencephalic area; and the PICA is not consistently present, being found in only 75% of the 27 specimens studied.
Basilar Artery↗
Posterior circulation revascularization.
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Cerebral Angiography↗
Artificial hearts, fractured valves, and other problems with medical devices.
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Equipment Failure↗
Reporting the failure of medical devices.
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Equipment Failure↗
Disturbance of plasmalemmal astrocytic assemblies in focal and selective cerebral ischemia.
Selective cerebral ischemia was induced in the caudate nucleus of seven normothermic anesthetized cats through transorbital clamping of the anterolateral penetrating lenticulostriated arteries. The plasmalemma of astrocytic foot processes has been studied with the freeze-fracture technique and conventional electron microscopy 10, 15 and 30 min after ischemia. After 15 min of circulatory arrest, assemblies of intramembrane particles (IMPs) disappear in some areas of astroglial perivascular plasmalemma in the ischemic caudate nucleus. Interastrocytic gap junctions do not change significantly. 30 min after ischemia, the pericapillary astroglial end foot is expanded and organelles are greatly perturbed (cytotoxic edema). Although the function of astrocytic intramembrane particle assemblies is unclear, it is postulated that the disappearance of this membrane specialization may play a role in the pathophysiology of cytotoxic astroglial edema.
Animals↗
Effects of needle shape on the integrity of the vascular endothelium.
Lesions generated by the passage of micro-needles through vessel walls are of concern because any lesion may significantly alter hemodynamics of an anastomosis. To study this problem, three different needles were tested on the exposed carotid arteries of 30 rats: the 100 mu taper point, the 100 mu cutting point, and the 75 mu taper point. Trauma generated by the penetration of needles was tested first as the needle and its attached suture was passed through the vessel, then the suture was left in place. One hour after penetration, the arteries were prepared for scanning electron microscopy. Differences between the 100 mu taper point and the 75 mu taper point were significant in terms of size and extent of lesions. An arc of endothelial cells surrounding the wounds showed flattening, tissue destruction and clotting. To minimize endothelial trauma, taper point needles are superior to cutting needles. The 100 mu cutting needle caused damage to the vessel wall in tissue cutting on needle penetration, causing a slit-like incision, and in aggregation of platelets at the puncture site.
Animals↗
Cerebral angiography and neuropsychological measurement: the twain may meet.
In a sample of 31 cerebral revascularization candidates, severity and dissemination of atherosclerosis on the cerebral angiogram were correlated with two of three global indicators of neurobehavioral impairment. Additionally, the angiographic rating was correlated with age and with an index of medical risk factors, but not with duration of the longest symptomatic episode. It seems likely that several variables, particularly collateral circulation, help to determine whether a given pattern of stenoses results in neuropsychological dysfunction and what type of behavioral deficit occurs. In many cases, the configuration of neuropsychological test scores may not directly mirror the pattern of cerebrovascular stenoses.
Adult↗
Middle cerebral artery reconstruction.
The authors have conducted an experimental study of the microanatomic features of the middle cerebral artery in unfixed human brains to assess the feasibility of reconstructive procedures within the Sylvian fissure. It was found that reconstructive procedures within the Sylvian fissure such as end-to-end, end-to-side, side-to-side, and grafting procedures were possible according to the anatomic data provided by our study. Possible surgical solutions to theoretical pathologic situations involving the middle cerebral artery vascular tree are highlighted and their feasibility is discussed.
Cerebral Arteries↗
Quantitative electron microscopic study of calcium accumulation in cerebral ischemia mitochondria.
Formation of calcium deposits in mitochondria is a consistent feature of irreversible injury in ischemic myocardium. We studied calcium accumulation in nerve cell mitochondria in a cat model 30 and 60 minutes after cerebral ischemia localized in the anterior part of the caudate nucleus and adjacent internal capsule. In control animals, calcium deposits were visible in synaptic vesicles, Golgi apparatus, mitochondria, lysosomes, and in glial and neuronal nuclei. After cerebral ischemia, findings included astrocytic swelling and degeneration of neurons, with an increase in calcium pyroantimoniate mitochondrial deposits. Content of intramitochondrial calcium deposits is related to duration of ischemia as well as the amount of cellular lesions.
Animals↗