Search PubMed⌕ Search

Biomedical subjects

M Dujovny

Publications and source records attributed to M Dujovny.

At least 19 recordsLinked to original sources
PubMed1995

Comparison of static conformal field with multiple noncoplanar arc techniques for stereotactic radiosurgery or stereotactic radiotherapy.

PURPOSE: Compare the use of static conformal fields with the use of multiple noncoplanar arcs for stereotactic radiosurgery or stereotactic radiotherapy treatment of intracranial lesions. Evaluate the efficacy of these treatment techniques to deliver dose distributions comparable to those considered acceptable in current radiotherapy practice. METHODS AND MATERIALS: A previously treated radiosurgery case of a patient presenting with an irregularly shaped intracranial lesion was selected. Using a three-dimensional (3D) treatment-planning system, treatment plans using a single isocenter multiple noncoplanar arc technique and multiple noncoplanar conformal static fields were generated. Isodose distributions and dose volume histograms (DVHs) were computed for each treatment plan. We required that the 80% (of maximum dose) isodose surface enclose the target volume for all treatment plans. The prescription isodose was set equal to the minimum target isodose. The DVHs were analyzed to evaluate and compare the different treatment plans. RESULTS: The dose distribution in the target volume becomes more uniform as the number of conformal fields increases. The volume of normal tissue receiving low doses (> 10% of prescription isodose) increases as the number of static fields increases. The single isocenter multiple arc plan treats the greatest volume of normal tissue to low doses, approximately 1.6 times more volume than that treated by four static fields. The volume of normal tissue receiving high (> 90% of prescription isodose) and intermediate (> 50% of prescription isodose) doses decreases by 29 and 22%, respectively, as the number of static fields is increased from four to eight. Increasing the number of static fields to 12 only further reduces the high and intermediate dose volumes by 10 and 6%, respectively. The volume receiving the prescription dose is more than 3.5 times larger than the target volume for all treatment plans. CONCLUSIONS: Use of a multiple noncoplanar conformal static field treatment technique can significantly reduce the volume of normal tissue receiving high and intermediate doses compared with a single isocenter multiple arc treatment technique, while providing a more uniform dose in the target volume. Close conformation of the prescription isodose to the target volume is not possible using static uniform conformal fields for target shapes lacking an axis of rotational symmetry or plane of mirror symmetry.

Brain Neoplasms↗
PubMed1995

Anatomy of the sympathetic pathways in the cavernous sinus.

We studied sympathetic fibres in the cavernous sinus in 40 unfixed specimens obtained from human cadavers. Sympathetic fibres in the cavernous sinus are understood to be grouped in a plexiform configuration surrounding the internal carotid artery and have a diffuse distribution among the sympathetic nerves. Our study, however, suggests that a more systematic arrangement of sympathetic pathways exists in the cavernous sinus. A detailed anatomical description of intracavernous sympathetic fibres contributes to academic anatomical knowledge and may have practical applications for 1. diagnostic interpretation of pathologic conditions involving the cavernous sinus, 2. recognition and orientation of anatomical structures during intracavernous surgical procedures, and 3. a deeper understanding of the sympathetic nerve supply to cerebral vasculature.

Carotid Artery, Internal↗
PubMed1995

Modified solution for filling MRI coordinate indicators for the ZD stereotactic frame.

Increased use of magnetic resonance imaging and magnetic resonance angiography in stereotactic planning highlight some technical problems in imaging. Visualization of markers during imaging are vital in stereotactic planning. In magnetic resonance imaging-guided stereotaxy, specially designed plates are used that contain water-based copper sulfate solutions as a marker. Replacement of copper sulfate solution is usually required after some time due to precipitation and leaking. The refilling procedure is quite cumbersome and can cause technical problems in imaging. In this study, we describe copper sulfate solution mixed with a water-soluble gel as a simple but useful alternative to water-based copper sulfate resolution to ease the refilling procedure and to overcome the air bubbles.

Copper↗
PubMed1995

Postoperative cognitive and single photon emission computed tomography assessment of patients with resection of perioperative high-risk arteriovenous malformations.

We studied the outcome of 10 patients who had undergone high-risk surgery for an arteriovenous malformation at our institution between November 1991 and November 1993. All of the lesions were located in the dominant (left) hemisphere. Perioperative risk was assessed by the location of the lesion in functionally eloquent cortex (seven patients) or deep structures (two patients) or the lesion's large volume (two patients). Our patients included six women and four men, and their ages ranged from 22 to 53 years (mean, 35.8). Our follow-up study included the evaluation of neurological sequelae but mainly emphasized the study of cognitive deficits (seven major functional clusters), the incidence of depression and behavioral changes, and the assessment of regional cerebral blood flow with single photon emission computed tomography. Six patients returned to a seemingly "normal" daily life with some minor deficits postoperatively, three developed contralateral hemiparesis, and one had disabling cognitive deficits. Our comprehensive cognitive assessment, in particular, showed that although patients might appear "normal" on a routine neurological examination, most patients showed a mild deficit in at least one cognitive function and three were severely impaired. In addition, the single photon emission computed tomographic studies pointed out hypoperfusion in more extensive regions than the surgical defects shown by magnetic resonance imaging or computed tomographic studies. These single photon emission computed tomography images helped to explain some of the cognitive and behavioral changes better than the anatomic studies. This information will make it possible for the physician to offer continuing supportive care for the patient in postoperative transition to normal life activities.

Adult↗
PubMed1995

Regional cerebral oxygen saturation during intra-arterial papaverine therapy for vasospasm: case report.

Cerebral arterial vasospasm continues to be a major secondary medical complication of aneurysmal subarachnoid hemorrhage. Despite hypervolemic hemodilution, arterial hypertension, and pharmacological therapy, morbidity and mortality due to vasospasm remain high. The authors discuss a patient with vasospasm who did not respond to traditional medical therapy and who underwent intra-arterial papaverine infusions while being monitored with transcranial cerebral oximetry. Oximetry during the procedure revealed significant improvements in brain regional saturation of oxygen, with the relief of vasospasm that correlated with clinical improvements in the patient's neurological status. Transcranial cerebral oximetry was used to monitor regional oxygen saturation throughout the angiographic and interventional procedures, providing continuous, real-time, clinically relevant information about the effects of vasospasm and its treatment.

Adult↗
PubMed1995

Microvascular anatomy of the anterior surface of the medulla oblongata and olive.

The arterial supply and the microanatomy of the anterior surface of the medulla oblongata and olive were studied in 11 cadaveric specimens, with investigation of the size, course, and length of the arteries. Two distinct anatomical entities divide the vascular supply in this region: 1) the pyramid, which is the anterior surface of the medulla; and 2) the olive, which is adjacent to the lateral aspect of the pyramid. Primary vascularization of the pyramid was via small branches of the anterior spinal artery, a branch of the vertebral artery. Minute perforators from the anterior spinal artery were found in all specimens. Arterial supply to the olive varied by location: its anterior aspect was primarily supplied by the anterior spinal artery; the upper portion of the posterior aspect of the olive was supplied by the vertebral artery, the anterior inferior cerebellar artery, and the basilar artery; and the middle and lower portions of the posterior aspect were fed by the vertebral artery and posterior inferior cerebellar artery. These arteries supplied the medulla through the small branches directed toward the olive. The authors observed a wide anastomotic net connecting the small arteries in this area. These patterns of microvascular supply of the pyramid and olive may deepen the understanding of clinical and pathological conditions resulting from arterial occlusion. The existence of an anastomotic net may account for the rare incidence of medullary infarction in the olive region.

Basilar Artery↗
PubMed1995

Use of transcranial cerebral oximetry to monitor regional cerebral oxygen saturation during neuroendovascular procedures.

Using transcranial cerebral oximetry, we monitored 30 patients who underwent cerebral angiography by the femoral route. Transcranial cerebral oximetry is a noninvasive technique of regional cerebral oxygen saturation measurement that uses near-infrared spectroscopy to differentiate oxyhemoglobin from reduced hemoglobin. Needle puncture, catheterization, and contrast media injection produced no significant peak changes in saturation from baseline. Acute and persistent decreases in oxygen saturation were associated with vascular complications and were detected before development of clinical symptoms. Greater changes in saturation were observed during several neuroendovascular procedures, indicating the development of complications, signaling a need to stop further endovascular manipulation.

Brain↗
PubMed1994

Clinical experience with transcranial cerebral oximetry.

Transcranial cerebral oximetry based on the principle of near-infrared spectroscopy has been successfully used in a variety of neurosurgical conditions, primarily those associated with disturbed cerebral circulation. The non-invasive technique of cerebral oximetry provides valuable information about brain oxygenation in patients with cerebral ischemia (due to occlusion or stenosis of the internal carotid artery). It is also used in intraoperative monitoring of carotid endarterectomy and surgical procedures performed under deep hypothermia and circulatory arrest, during neuroendovascular procedures, and in critical care settings (in patients with arterial vasospasm and during the terminal period). This article describes our preliminary clinical experience with the use of this new technique and summarizes the current literature on clinical and experimental use of transcranial cerebral oximetry.

Algorithms↗
PubMed1994

Monitoring the intracranial aneurysm patient.

The perioperative management of aneurysmal subarachnoidal haemorrhage is challenging and often requires an extensive team work. Unfortunately, there is no uniform system applied for perioperative monitoring of patients with subarachnoid haemorrhage. The new developing technology enhances our monitoring capability with subsequent impact on patient's outcome. This article presents a review of current monitoring modalities applicable to patients with subarachnoid haemorrhage with emphasis on the central nervous system and some of the authors' experience.

Humans↗
PubMed1994

Pineal region: rare location of a cavernous haemangioma.

Cavernous haemangiomas are commonly located within the central nervous system. There are only 11 cases of this malformation found in the pineal region reported in the literature, and only four of them have documenting photomicrographs. Very little has been written about diagnostic features of these tumours when they occur in this area. We describe our diagnosis of a cavernous haemangioma in the pineal region with special emphasis on its radiologic and histologic aspects.

Adult↗
PubMed1994

Microsurgical anatomy of the intracranial part of the vertebral artery.

We studied the intracranial portion of the vertebral artery and its branches in 11 cadaveric specimens. We evaluated the course of vessels and their dimensions (external diameter and length), as well as relationships between each of them. The vertebral artery was larger on the left side in two cases, on the right in five cases, and equal on both sides in four cases. The right and left vertebral arteries joined each other forming the basilar artery at the level of the pontomedullary junction in four cases, 2 mm below it in one case, and 1 to 7 mm above it in six cases. We divided all branches of the intracranial vertebral artery into two groups: the medial branches and the lateral branches. Two major types of medial branches were observed: the anterior spinal artery and the branches of the foramen caecum. The origin of the anterior spinal artery was located 6.5 mm (5-11 mm) proximal to vertebrobasilar junction on the right and 8.5 mm (6-17 mm) on the left. The anterior spinal artery was absent on the right in two cases and on the left in one. Branches arising from the vertebral artery to the foramen caecum were found in four brains. Lateral branches originated from the posterolateral or lateral aspect of vertebral artery. The posterior inferior cerebellar artery, the largest branch of the vertebral artery, was included in this group. Other branches were mostly located between the origin of the posterior inferior cerebellar artery and the vertebrobasilar junction. Forty-six lateral branches originating from the vertebral artery were found in 11 brains (26 on the right and 20 on the left). Lateral branches widely anastomosed with perforators from the basilar artery, posterior inferior cerebral artery, and the anterior inferior cerebellar artery.

Arteriovenous Anastomosis↗
PubMed1994

Microsurgical anatomy of the trigeminal nerve.

We studied the trigeminal nerve in the middle cranial fossa in 20 cadaveric specimens (10 fixed skull base). Specifically, we analysed the relationships among the gasserion or trigeminal ganglion (herein referred to as the gasserion ganglion), the internal carotid artery, and the petrous bone. The dimensions of the trigeminal ganglia, the length from the ganglia to the exit foramina, and the width of the ophthalmic, maxillary, and manidibular nerves were also studied. The foramina of the middle cranial fossa were measured for their diameter and their distance from each other. Our paper compares our study to previous studies and the measurements taken in those studies. The lesions affecting the ganglion and the nerves are discussed and the surgical approaches to the middle cranial fossa, the petrous bone, and the upper clivus are also reviewed.

Adult↗
PubMed1994

Microsurgical anatomy of the supratentorial arachnoidal trabecular membranes and cisterns.

We examined the microsurgical anatomy of the supratentorial subarachnoid cisterns with a surgical microscope in 20 brains prepared using the immersion technique. The adult brains were immersed in Ringer's solution and air was injected into the subarachnoid cisterns while the brains remained submerged in solution. We identified nine trabecular membranes that limit the 15 cisterns. We specifically looked at the anatomical relationship between the supratentorial trabecular membranes and cisterns to their corresponding vessels and cranial nerves. The cistern divisions and the dispositions of trabecular membranes were closely related to the vascular division patterns of the principal brain arteries. A clear and thorough understanding of the neuroanatomical structures of the subarachnoid cisterns is important because they provide natural pathways to neurovascular and cranial nerve structures. These pathways allow access to intracranial arteries, veins, and nerves during microvascular procedures without disturbing surrounding important brain structures.

Adolescent↗
PubMed1994

Language-activated single-photon emission tomography imaging in the evaluation of language lateralization--evidence from a case of crossed aphasia: case report.

We report a right-handed patient who developed a nonfluent aphasia after surgery for a right parietal arteriovenous malformation. Resting brain single-photon emission tomography displayed decreased regional cerebral blood flow only in the right hemisphere, with spared regional cerebral blood flow in the left hemisphere. Single-photon emission tomography performed after a language activation task (Boston Naming Task) showed a consistent area of increased regional cerebral blood flow in the right inferior and posterior frontal lobe, supporting a right hemisphere dominance for language. These results suggest a potential role for this noninvasive study in the evaluation of language lateralization.

Adult↗
PubMed1992

Stereotactic endoscopic interventions in cystic and intraventricular brain lesions.

Image guided stereotaxis is an accurate and safe method of directing therapy to target volumes defined in two-dimensional (2D) multiplanes or three-dimensional (3D) perspectives using computer reconstruction of image data. The major limitations of stereotactic techniques are related to a lack of intraoperative visualization and direct monitoring of the procedures and to changes of intracranial coordinates after decompression of cystic lesions or aspiration of cerebrospinal fluid in the management of intraventricular lesions. Endoscopic laser stereotaxis (ELS) involves integration of rigid-flexible endoscopy and Nd-YAG laser to 3D-2D multiplanar image-guided stereotactic procedures. The major advantages of ELS include: direct intraoperative visualization, hemostasis, evacuation or resection assessment, and wide exploration of intracranial cavities or ventricles. The technique allows safe aspiration, biopsy, and resection or internal decompression of deep and subcortical intracranial lesions. ELS has proved to be safe and effective in the management of 76 clinical cases and appears to be a promising technique in the management of cystic and intraventricular lesions.

Brain Diseases↗
PubMed1992

Microsurgical anatomy of the lower basilar artery.

This study was designed to study the microvascular anatomy of the basilar artery between the superior cerebellar artery and the vertebrobasilar junction (i.e. the lower basilar artery). Twenty unfixed brains were injected with silicone rubber solution and studied with a Zeiss OPMI microscope. The length of this segment of the basilar artery was 28.1 + 1.35 mm and its course was straight in 9 (45%) brains, curved in 7 (35%) and tortuous in 4 (20%). The total number of perforators found in 20 brains was 340 with an average of 17 per brain. Of these, 118 (34.7%) were median and 222 (65.2%) were lateral. Median branches had a mean length of 5.8 + 1.25 mm, whereas left and right lateral branches had a mean length of 16 + 1.25 mm and 16 + 1.58 mm respectively.

Autopsy↗
PubMed1992

Stereotactic management of midline brain lesions.

Eighty-seven patients, aged 10 months to 92 years, with midline brain lesions were treated using stereotactic techniques at our institution between January 1987 and June 1990. A total of 119 stereotactic procedures were performed with no operative mortality. Procedures included 53 biopsies only, 22 endoscopic laser decompressions, 8 stereotactic microsurgical resections, 9 permanent implants of 125I, 12 temporary implants of 125I, 11 cyst aspirations, 2 cystoperitoneal shunts and 2 intracavitary 32P. The morbidity rate was 4.21%. Local anesthesia was used in 106 of the procedures (89%). Accurate diagnosis was achieved in all cases. Image guidance and stereotactic techniques open new frontiers in the diagnostic and therapeutic management of deep-seated midline intraparenchymal lesions.

Biopsy↗