bluuebunny/crossref_metadata_2025_split huggingface dataset:
What Factors Are Related to Impairment of Cerebrovascular Reserve before and after Arteriovenous Malformation Resection? A Cerebral Blood Flow Study Using Xenon-enhanced Computed Tomography
Authors: Roost Dirk Van , Schramm Johannes 
Published: July 2004

Abstract

OBJECTIVE
To examine the incidence and possible determinants of impaired vascular reserve in arteriovenous malformation (AVM)-affected brain, before and after surgery.

METHODS
In a prospective study of 30 patients, the regional cerebrovascular reserve capacity (rCRC) and the vasodilated regional cerebral blood flow (rCBF) were assessed during an acetazolamide challenge, using xenon-enhanced computed tomography, before and after complete AVM resection. Single brain slices at the level of the basal ganglia were examined, and scanning through the AVMs was avoided. Five regions of interest in the AVM-bearing hemisphere were compared with their counterparts in the unaffected hemisphere. Vasodilated rCBF reductions of at least 20% in one or more regions of interest and rCRC values of less than 10 ml/100 g/min were considered to be significant.

RESULTS
Ipsilateral vasodilated rCBF was significantly reduced in 17 patients before surgery and 15 patients after surgery. Ipsilateral rCRC was impaired in 14 patients before surgery and 12 patients after surgery. Large AVM size, venous congestion, and AVM-related vascular territories were correlated with impaired vascular reserve in AVM-nonadjacent brain tissue before surgery. Similar correlations were observed after surgery, except that not AVM size but a large number of AVM-supplying vascular territories was correlated. Moreover, the smallest AVMs and those supplied by a single vascular territory, as well as hemorrhage and nonhemorrhagic neurological deficits as presenting symptoms, were correlated with reduced ipsilateral vasodilated rCBF before surgery. Among patients with AVMs and nonhemorrhagic epilepsy, a trend of impaired cerebrovascular reserve was observed. In the only case of postresectional “breakthrough,” the preoperative rCRC was not impaired but abnormally high.

CONCLUSION
Among the determinants of impaired cerebrovascular reserve, AVM size is already a constituent of current grading scales and decision-making paradigms, whereas factors such as venous congestion have been less closely considered or less obvious but may deserve increased attention in the future. Nonhemorrhagic epilepsy in patients with AVMs may constitute the clinical equivalent of chronic cerebral ischemia in a murine model. Postresectional breakthrough may be partly attributable to individual predisposition to excessive vasoreactivity in the whole brain.
Novel, Compact, Intraoperative Magnetic Resonance Imaging-guided System for Conventional Neurosurgical Operating Rooms
Authors: Hadani Moshe , Spiegelman Roberto , Feldman Zeev , Berkenstadt Haim , Ram Zvi 
Published: July 2004

Abstract

OBJECTIVE
Preliminary clinical experience with a novel, compact, intraoperative magnetic resonance imaging (MRI)-guided system that can be used in an ordinary operating room is presented.

DESCRIPTION OF INSTRUMENTATION
The system features an MRI scanner integrated with an optical and MRI tracking system. Scanning and navigation, which are operated by the surgeon, are controlled by an in-room computer workstation with a liquid crystal display screen. The scanner includes a 0.12-T permanent magnet with a 25-cm vertical gap, accommodating the patient's head. The field of view is 11 × 16 cm, encompassing the surgical area of interest. The magnet is mounted on a transportable gantry that can be positioned under the surgical table when not in use for scanning, thus rendering the surgical environment unmodified and allowing the use of standard instruments. The features of the integrated navigation system allow flap planning and intraoperative tracking based on updated images acquired during surgery.

OPERATIVE TECHNIQUE
Twenty patients with brain tumors were surgically treated using craniotomy or transsphenoidal approaches. One patient underwent conscious craniotomy with cortical mapping, and two underwent electrocorticography.

EXPERIENCE AND RESULTS
Planning was accurate. Resection control images were obtained for all patients during surgery, with precise localization of residual tumor tissue. There were no surgical complications related to the use of the system.

CONCLUSION
This intraoperative MRI system can function in a normal operating room modified only to eliminate radiofrequency interference. The operative environment is normal, and standard instruments can be used. The scanning and navigation capabilities of the system eliminate the inaccuracies that may result from brain shift. This novel type of intraoperative MRI system represents another step toward the introduction of the modality as a standard method in neurosurgery.
Reversal of Increased Intracranial Pressure with Removal of a Torcular Epidermoid: Case Report
Authors: Lam Cornelius H. , Solomon Robin K. , Clark H. Brent , Casey Sean O. 
Published: July 2004

Abstract

OBJECTIVE AND IMPORTANCE
Venous obstruction has been postulated as a cause of increased intracranial pressure, but it has been documented rarely. We present a case of obstruction of the torcula by a slow-growing epidermoid. The tumor caused increased intracranial pressure, which was relieved when it was excised. In addition, the torcular epidermoid is associated with a bifid straight sinus.

CLINICAL PRESENTATION
A 35-year-old man presented with a headache and a lump on the back of the head. Physical examination revealed a firm, bony lesion approximately 4 × 4 cm in size. Lumbar puncture demonstrated an intraspinal pressure of 39 cm H2O. Neuroradiological studies revealed an epidermoid that compressed and almost completely occluded the torcula.

INTERVENTION
After the tumor was resected, the intraspinal pressure decreased to 19 cm H2O and remained stable 6 months later.

CONCLUSION
Pure venous obstruction causes increased intracranial pressure. Removal of the obstruction relieves the intracranial hypertension. In addition, computed tomographic venography is a safe and easy method of documenting torcular anatomy, and it was useful in the follow-up of this patient. Computed tomographic venography can demonstrate a double straight sinus, which is a congenital variant that may be associated with the epidermoid.
Aneurysms of the Lateral Spinal Artery: Report of Two Cases
Authors: Chen Clark C. , Bellon Richard J. , Ogilvy Christopher S. , Putman Christopher M. 
Published: July 2004

Abstract

OBJECTIVE AND IMPORTANCE
The goal of this report was to describe aneurysms arising from the lateral spinal artery. The locations of aneurysms contributing to subarachnoid hemorrhage (SAH) have been well characterized and are primarily in the circle of Willis or at the bifurcation points of the internal carotid artery or the vertebrobasilar system. Although the spinal arteries are also in direct communication with the subarachnoid space, aneurysms of these arteries that lead to SAH are rare. To date, only aneurysms of the anterior and posterior spinal arteries have been described. In this communication, we report two patients with aneurysms of the lateral spinal artery who presented with SAH.

CLINICAL PRESENTATION
Review of our neurointerventional database from 1997 to the present revealed two patients with lateral spinal artery aneurysms. The medical records, as well as the operative and radiological findings, were reviewed for both patients. In both cases, the lateral spinal arteries were involved as collateral pathways for occlusive vertebral lesions, suggesting hemodynamic stress as a cause.

INTERVENTION
Endovascular treatment was attempted in both cases and was successful in one; open surgery, with aneurysm resection, was performed in the other case. We review the vascular anatomic features of the spinal cord as they relate to the lateral spinal artery, as well as treatment options for lateral spinal artery aneurysms.

CONCLUSION
Lateral spinal artery aneurysms are a rare cause of SAH. Both endovascular and surgical treatment options are available.
Embolization of Arteriovenous Malformations with Onyx: Clinicopathological Experience in 23 Patients
Authors: Jahan Reza , Murayama Yuichi , Gobin Y. Pierre , Duckwiler Gary R. , Vinters Harry V. , Viñuela Fernando 
Published: July 2004

Abstract

OBJECTIVE
To report our experience in treatment of arteriovenous malformations (AVMs) using a new liquid embolic agent, Onyx (Micro Therapeutics, Inc., Irvine, CA).

METHODS
Between January 1998 and May 1999, 23 patients (8 men and 15 women) were treated. The patients' average age was 40 years, with seizure being the most common presenting symptom (39%). The average Spetzler-Martin grade on presentation was 3. The average AVM volume before embolization was 14.5 cm3.

RESULTS
We observed an average 63% reduction in AVM volume after 129 arterial feeders were embolized. There were four adverse events. Two patients experienced ischemia because of inadvertent occlusion of an arterial feeder. One of these patients made a full recovery, but the other patient had a permanent deficit. Two other patients experienced transient neurological deficits that resolved within 1 week of embolization. Permanent morbidity was thus 4% (1 of 23 patients). There were no deaths. Twelve patients underwent subsequent radiosurgery, and 11 patients had surgery that resulted in complete resection of their AVMs. Histopathological examinations showed mild acute inflammation in specimens resected 1 day after embolization. Chronic inflammatory changes were observed in specimens resected more than 4 days after embolization. In two patients, angionecrosis of the embolized vessels was noted. No evidence of parenchymal hemorrhage was observed in these patients, and vessel wall integrity was maintained as well.

CONCLUSION
Onyx is a new nonadhesive liquid embolic agent that has been used to treat 23 patients at our institution with good results. Its nonadhesive nature and ease of use make it a promising agent in the future treatment of AVMs.
Multimodal Cranial Neuronavigation: Direct Integration of Functional Magnetic Resonance Imaging and Positron Emission Tomography Data: Technical Note
Authors: Braun Veit , Dempf Sibylle , Tomczak Reinhard , Wunderlich Arthur , Weller Rolf , Richter Hans-Peter 
Published: July 2004

Abstract

OBJECTIVE
This is the first report of the direct integration of functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) data into cranial neuronavigation.

METHODS
In a patient with a left precentral oligodendroglioma (World Health Organization Grade III), the Zeiss MKM system (Carl Zeiss Co., Oberkochen, Germany) was used for navigation based on thin-slice, T1-weighted, contrast-enhanced magnetic resonance imaging (MRI) scans. fMRI and methionine PET data were integrated by landmark matching, with reference to skin fiducials.

RESULTS
The inaccuracy of the image fusion between fMRI and T1-weighted MRI data was 1.7 mm, that between PET and T1-weighted MRI data was 4.3 mm, and that for the subsequent registration of the navigation was 1.2 mm. The correct fMRI localization of the precentral gyrus was intraoperatively verified by cortical somatosensory evoked potential (phase-reversal) monitoring. Although the tumor was not clearly defined in the MRI scans, [11C]methionine PET demonstrated a clear tumor border, enabling us to achieve gross total tumor removal without postoperative functional deficits.

CONCLUSION
Functional neuronavigation permits observation and preservation of relevant brain areas. Other functional areas (such as short-term memory areas) that can be detected only by fMRI might also warrant future monitoring. The simultaneous integration of fMRI and PET data adds a new dimension to cranial neuronavigation, enabling the observation of tumors in relation to functional cortical areas (in our case, the motor strip).
Transsphenoidal Surgery for Acromegaly: Endocrinological Follow-up of 98 Patients
Authors: Shimon Ilan , Cohen Zvi R. , Ram Zvi , Hadani Moshe 
Published: July 2004

Abstract

OBJECTIVE
Transsphenoidal surgery is the preferred treatment modality for growth hormone (GH)-secreting pituitary adenomas. In many series, the reported postoperative remission is based mainly on achievement of GH levels less than 2 ng/ml. Strict criteria for insulin-like growth factor I normalization and even lower GH levels (&lt;1 ng/ml) are now suggested to define cure of acromegaly, but the evidence does not yet support such low GH levels in epidemiological follow-up. We analyzed our postoperative results in a large cohort of patients with acromegaly.

METHODS
Ninety-eight patients harboring GH-secreting adenomas (46 microadenomas and 52 macroadenomas) underwent transsphenoidal surgery between 1990 and 1999. Ninety-one patients were operated for the first time, and 12 patients underwent reoperations because of previous surgical failure (7 had undergone surgery elsewhere previously). Biochemical remission was defined as a repeated fasting or glucose-suppressed GH level of 2 ng/ml or less, and a normal insulin-like growth factor I level.

RESULTS
Remission was achieved in 74% of all patients after one operation, including 84% of patients with microadenomas and 64% of patients with macroadenomas. Seventy-three percent of patients with macroadenomas 11 to 20 mm in size achieved remission, as compared with a 20% remission rate for patients with adenomas larger than 20 mm. Patients with preoperative random GH levels lower than 50 ng/ml had a better outcome (85% remission), whereas GH greater than 50 ng/ml was associated with remission in 30% of the patients. Only one of the patients (8%) with postoperative active disease who underwent a second operation achieved remission. Recurrence was rare (one patient), and all failed surgical attempts could be detected during the immediate postoperative evaluation.

CONCLUSION
On the basis of strict postoperative GH and insulin-like growth factor I criteria to define remission, our series demonstrates the efficacy of transsphenoidal surgery for acromegalic patients with microadenomas and noninvasive macroadenomas. However, patients with large adenomas (&gt;20 mm) and preoperative GH greater than 50 ng/ml have a poor prognosis and require adjunctive medical or radiation therapy to control GH hypersecretion.
Angioplasty of Intracranial Occlusion Resistant to Thrombolysis in Acute Ischemic Stroke
Authors: Ringer Andrew J. , Qureshi Adnan I. , Fessler Richard D. , Guterman Lee R. , Hopkins L. Nelson 
Published: July 2004

Abstract

OBJECTIVE
Thrombolysis has been demonstrated to improve revascularization and outcome in patients with acute ischemic stroke. Many centers now apply thrombolytic therapy locally via intra-arterial infusion. One therapeutic benefit is the ability to cross soft clots with a guidewire and to perform mechanical thrombolysis. In some instances, reopened arteries reocclude as a result of either thrombosis or vasospasm. We report the use of balloon angioplasty during thrombolysis for acute stroke.

METHODS
From June 1995 through June 1999, 49 patients underwent intra-arterial therapy for acute stroke. In this group, nine patients (seven men and two women) were treated with balloon angioplasty after inadequate recanalization with thrombolytic infusion. The mean age of these patients was 67.9 years. Nine matched control patients who underwent thrombolysis alone without angioplasty were chosen for comparison.

RESULTS
In the group of nine patients who had angioplasty, the mean National Institutes of Health Stroke Scale score at presentation was 21.8 ± 5.4. Four patients had residual distal occlusion after angioplasty, and one patient had a hemorrhagic conversion. Of the five patients in which recanalization was successful, none had reocclusion of the balloon-dilated vessel. The mean score at 30 days for the five survivors was 12.6 ± 14.9, for an improvement of 7.0 ± 14.2. Among the nine control patients, the mean score at presentation was 20.3 ± 5.2; the mean score at 30 days for the five survivors was 19.4 ± 7.7, for an improvement of 4.2 ± 7.8.

CONCLUSION
In our experience, balloon angioplasty is a safe, effective adjuvant therapy in patients who are resistant to intra-arterial thrombolysis. The use of balloon angioplasty may prevent reocclusion in a stenotic artery and permit distal infusion of thrombolytic agents.
Resection of a Giant Intracranial Dural Arteriovenous Fistula with the Use of Low-flow Deep Hypothermic Cardiopulmonary Bypass after Partial Embolization: Technical Case Report
Authors: Dufour Henry , Levrier Olivier , Bruder Nicolas , Messana Thierry , Grisoli François 
Published: July 2004

Abstract

OBJECTIVE AND IMPORTANCE
To describe the surgical resection of a giant intracerebral arteriovenous fistula with involvement of dura mater and surrounding bone. Intraoperative bleeding was controlled by hypothermic circulatory arrest.

CLINICAL PRESENTATION
This 46-year-old woman complained of persistent headache for 1 year; her diagnostic workup revealed the presence of an arteriovenous fistula in the dura mater of the left temporal region fed by the meningeal artery of the external and internal carotid arteries, with normal run-off into Labbé's and Trolard's veins. Magnetic resonance imaging depicted a Chiari I malformation that was most likely a result of insufficient cerebral venous drainage.

INTERVENTION
In preparation for surgery, staged embolization of feeders from the left meningeal artery and the left occipital artery was performed under controlled hypotension. This procedure failed to achieve a significant reduction in flow because of the immediate recruitment of internal branches of the internal carotid artery and dural branches of the right external carotid artery. Surgical treatment was undertaken without further embolization. Because of involvement of surrounding bone and the high risk of uncontrollable bleeding, the procedure was carried out with the patient under deep hypothermic cardiopulmonary bypass. Forty-five minutes of low flow (1.5 L/min) at 18°C allowed total resection of the involved dura mater and surrounding bone. Postoperative recovery was marked by left brain edema that disappeared within 10 days. Findings on follow-up angiography were normal, and the patient was discharged with no neurological deficit.

CONCLUSION
Low-flow deep hypothermic cardiopulmonary bypass can be used to control intraoperative bleeding for surgical excision of a giant intracerebral dural arteriovenous fistula.
Improved Cerebral Perfusion and Metabolism after Stenting for Basilar Artery Stenosis: Technical Case Report
Authors: Uchiyama Naoyuki , Kida Shinya , Watanabe Takuya , Yamashita Junkoh , Matsui Osamu 
Published: July 2004

Abstract

OBJECTIVE
Recent advances in stent technology have allowed the introduction of more flexible stents that may be tracked more easily in the intracranial vessels. We present a patient with improved cerebral blood flow and metabolism as assessed by positron emission tomography after stent-assisted angioplasty for symptomatic basilar artery stenosis.

CLINICAL PRESENTATION
A 62-year-old man, who had undergone left superficial temporal artery to middle cerebral artery bypass surgery for left internal carotid artery occlusion 10 years previously, presented with dizziness, blurred vision, and memory disturbance. Angiography revealed severe stenosis of the proximal basilar artery. Positron emission tomographic scans revealed decreased cerebral blood flow associated with increased oxygen extraction fraction in the entire brain, particularly in the posterior circulation and the left middle cerebral artery territory. Despite medical treatment, the patient experienced worsening visual disturbance and right-sided motor weakness.

INTERVENTION
Ticlopidine and aspirin were used as antiplatelet agents. In addition, we used argatroban, which is a direct thrombin inhibitor, as an anticoagulant during the procedure. Predilation with a coronary artery balloon was performed, followed by placement of a GFX 3- by 8-mm stent (Arterial Vascular Engineering, Santa Rosa, CA), with excellent angiographic results. The patient made a good neurological recovery, and the postoperative positron emission tomographic scan demonstrated increases in both cerebral blood flow and cerebral metabolic rate of oxygen with a normalization of oxygen extraction fraction.

CONCLUSION
Stent-assisted angioplasty can provide a favorable clinical course as well as improved cerebral perfusion and metabolism for a patient with basilar artery stenosis. Long-term follow-up data and additional clinical experience are required to assess the durability of this approach.
The Nature and Fate of Punctate (Type IV) Cavernous Malformations
Authors: Clatterbuck Richard E. , Elmaci Ilhan , Rigamonti Daniele 
Published: July 2004

Abstract

OBJECTIVE
Four types of cavernous malformations (Types I–IV) have been described on the basis of their magnetic resonance imaging (MRI) appearance. The nature of the Type IV cavernous malformation is unclear. It has been suggested that these small lesions, which are well observed only on gradient echo MRI scans, are capillary telangiectasias. We sought to understand the relationship of Type IV cavernous malformations to the other cavernous malformation subtypes.

METHODS
We examined serial MRI scans obtained between 1987 and 2000 from 68 patients with more than 228 cavernous malformations. Sixteen patients harbored Type IV cavernous malformations (total, &gt;114 Type IV lesions). Spin echo T1-weighted, T2-weighted, proton density, and (when available) gradient echo MRI scans were reviewed. Cavernous malformations that met the Zabramski criteria for Type IV (poorly observed on T1- and T2-weighted images) were reviewed in serial scans from individual patients to characterize their radiographic behavior over time.

RESULTS
Type IV cavernous malformations were best observed on gradient echo images and have an MRI appearance distinct from capillary telangiectasias. Proton density images demonstrate more Type IV lesions than T1- and T2-weighted images, but far fewer Type IV lesions than gradient echo images. When observed on T1- and T2-weighted images, Type IV cavernous malformations are generally punctate and hypointense. These lesions rarely enhance with gadolinium. Four of the Type IV cavernous malformations observed serially evolved into Type I and Type II cavernous malformations, for an approximate rate of progression of 0.05 per patient year.

CONCLUSION
Although most Type IV cavernous malformations remain stable over time, a small subset of these lesions progress into Types I and II cavernous malformations.