Publications by authors named "David B Niemann"

Background: The angiographic evaluation of previously coiled aneurysms can be difficult yet remains critical for determining re-treatment.

Objective: The main objective of this study was to determine the inter-rater reliability for both the Raymond Scale and per cent embolization among a group of neurointerventionalists evaluating previously embolized aneurysms.

Methods: A panel of 15 neurointerventionalists examined 92 distinct cases of immediate post-coil embolization and 1 year post-embolization angiographs.

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Currently, clinical acquisition of IV 3D-DSA requires two separate scans: one mask scan without contrast medium and a filled scan with contrast injection. Having two separate scans adds radiation dose to the patient and increases the likelihood of suffering inadvertent patient motion induced mis-registration and the associated mis-registraion artifacts in IV 3D-DSA images. In this paper, a new technique, SMART-RECON is introduced to generate IV 3D-DSA images from a single Cone Beam CT (CBCT) acquisition to eliminate the mask scan.

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Introduction: Non-aneurysmal spontaneous subarachnoid hemorrhage is characterized by an accumulation of a limited amount of subarachnoid hemorrhage, predominantly around the midbrain, and a lack of blood in the brain parenchyma or ventricular system. It represents 5% of all spontaneous subarachnoid hemorrhage cases. In spite of extensive investigation, understanding of the mechanisms leading to perimesencephalic non-aneurysmal subarachnoid hemorrhage remains incompletely defined.

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Purpose: Simulation techniques in neurosurgical training are becoming more important. The purpose of this study was to determine whether silicone vascular models used in the angiography suite can render improvement in trainee performance and safety in neuroendovascular procedures.

Methods: 10 residents from neurosurgery and radiology training programs were asked to perform a diagnostic angiogram on a silicone based vascular model (United Biologics, Tustin, USA).

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Background: Although, the relationship of spontaneous subarachnoid hemorrhage (SAH) to climatic or circadian factors has been widely studied, epidemiologic, circardian and climatic factors in non-aneurysmal SAH (naSAH), particularly perimesencephalic SAH (PMH), has not been reported before.

Objective: For the first time, demographic, climatic, and circadian variables are examined together as possible contributing factors comparing aSAH and naSAH.

Methods: We reviewed records for 384 patients admitted to University of Wisconsin Neurosurgery Service from January 2005 to December 2010 with spontaneous non-traumatic SAH.

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Background: Bilateral fenestration of the A1 segment of anterior cerebral artery (ACA) is an uncommon anomaly. Our objective is to describe two cases with this anomaly and to review the literature.

Case Description: A 50-year-old woman presented with subarachnoid hemorrhage from a ruptured A1 aneurysm.

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Background: Spontaneous fusiform aneurysms of the middle cerebral artery (sfaMCA) are quite uncommon and tend to occur in young adults. The use of superselective angiography for ruptured and unruptured aneurysms can help delineate vital angioarchitecture and assist with perioperative planning and treatment modality. The use of superselective Wada testing (SWT) for treatment of a ruptured sfaMCA involving the dominant hemisphere, however, has never been described in the English literature.

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Background And Purpose: The purpose of this study is to present 12-month follow-up results for a series of patients undergoing percutaneous transluminal angioplasty and stenting with the Gateway-Wingspan stenting system (Boston Scientific) for the treatment of symptomatic intracranial atherostenosis.

Methods: Clinical and angiographic follow-up results were recorded for patients from 5 participating institutions. Primary end points were stroke or death within 30 days of the stenting procedure or ipsilateral stroke after 30 days.

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We present approaches for using thin film polymeric electrode arrays for use in applications of minimally invasive neurological monitoring. The flexibility and unique surface properties of the thin-film polyimide substrate in combination with a compact device platform make them amenable to a variety of surgical implantation procedures. Using a rapid-prototyping and fabrication technique, arrays of various geometries can be fabricated within a week.

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Background And Purpose: In-stent restenosis (ISR) occurs in approximately one-third of patients after the percutaneous transluminal angioplasty and stenting of intracranial atherosclerotic lesions with the Wingspan system. We review our experience with target lesion revascularization (TLR) for ISR after Wingspan treatment.

Methods: Clinical and angiographic follow-up results were recorded for all patients from 5 participating institutions in our US Wingspan Registry.

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Objective: A classification system developed to characterize in-stent restenosis (ISR) after coronary percutaneous transluminal angioplasty with stenting was modified and applied to describe the appearance and distribution of ISR occurring after Wingspan (Boston Scientific, Fremont, CA) intracranial percutaneous transluminal angioplasty with stenting.

Methods: A prospective, intention-to-treat, multicenter registry of Wingspan treatment for symptomatic intracranial atherosclerotic disease was maintained. Clinical and angiographic follow-up results were recorded.

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Object: There is little evidence addressing whether procedures requiring adjunctive devices lead to an increased frequency of thromboembolic complications. The authors report their experience with 155 aneurysms treated with and without adjunctive devices.

Methods: The authors retrospectively reviewed their last 155 aneurysm coil placement procedures.

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Object: Arterial bypass is an important method of treating intracranial disease requiring sacrifice of the parent vessel. The conduits for extracranial-intracranial (EC-IC) bypass surgery include the superficial temporal artery, occipital artery, superior thyroid artery, radial artery, and saphenous vein (long or short). In an aging population with an increased prevalence of vascular disease, conduits for EC-IC bypass may be in short supply in some patients.

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Objective: Wingspan (Boston Scientific, Fremont, CA) is a self-expanding stent designed specifically for the treatment of symptomatic intracranial atheromatous disease. The current series reports the observed incidence of in-stent restenosis (ISR) and thrombosis on angiographic follow-up.

Methods: A prospective, intent-to-treat registry of patients in whom the Wingspan stent system was used to treat symptomatic intracranial atheromatous disease was maintained at five participating institutions.

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Introduction: Previously, endovascular treatment of stenosis related to intracranial atherosclerosis (ICAD) involving arteries measuring less than 2 mm in diameter was limited. To our knowledge, there are no reports in the literature addressing stent placement for treatment of stenosis in arteries of this size.

Methods: Four patients aged 33 to 80 years (mean 57.

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Background And Purpose: The current report details our initial periprocedural experience with Wingspan (Boston Scientific/Target), the first self-expanding stent system designed for the treatment of intracranial atheromatous disease.

Methods: All patients undergoing angioplasty and stenting with the Gateway balloon-Wingspan stent system were prospectively tracked.

Results: During a 9-month period, treatment with the stent system was attempted in 78 patients (average age, 63.

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Object: Digital subtraction (DS) angiography is the gold standard for detecting cerebral vasospasm after subarachnoid hemorrhage (SAH). Computed tomography (CT) perfusion is a recently developed modality for the evaluation of cerebral hemodynamics. This study was conducted to evaluate the potential of using CT perfusion to detect vasospasm in patients with SAH.

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Computed tomography (CT) perfusion is traditionally performed using iodinated contrast, but this can be problematic in patients with impaired renal function or contrast allergy. We report a case of a 63-year-old man whose medical history was complicated by chronic renal failure, which was exacerbated after placement of a left cervical internal carotid artery stent by 70% stenosis and left hemisphere perfusion deficit. On a follow-up clinic visit, because of the patient s chronic renal failure, CT perfusion was performed successfully using gadolinium without further renal complications.

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Introduction: There are no well-established physiologic or neuropsychological criteria for identifying which patients with stenosis of the cervicocerebral vessels are at high risk of stroke or cognitive impairment. Our purpose was to evaluate changes in cognitive performance and cerebral perfusion associated with endovascular stent placement of the cervicocerebral vessels.

Methods: A consecutive series of 20 patients, 31-88 years of age, who underwent 21 stent procedures for arterial stenosis (10 extracranial carotid stents [ECS], four intracranial carotid stents [ICS], and seven extra- or intracranial vertebrobasilar stents [VBS]) was investigated retrospectively.

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A case of cranial-based metastatic non-Hodgkin lymphoma with cerebral vascular compromise is presented. The patient underwent intracranial endovascular stent placement resulting in an improvement in his symptoms. This is the first reported case of endovascular stent placement for an intracranial neoplasm in the literature to date.

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The authors describe the novel use of cerebral perfusion computerized tomography studies to evaluate the effectiveness of internal carotid artery stent placement in a man with symptomatic transient ischemic attacks caused by tandem stenoses of the internal carotid and middle cerebral arteries.

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Venous outlet obstruction has recently been reported to be a potentially treatable cause of benign intracranial hypertension (BIH). In the English-language literature only 18 cases, all from the UK and Australia, involving the use of transverse sinus stenosis stent treatment for BIH have been reported; the youngest patient to receive treatment was a 17-year-old girl. The authors report the case of a 15-year-old boy who presented with headache, papilledema, decreased visual acuity, and diploplia who underwent successful unilateral transverse sinus stenosis stenting and experienced complete resolution of symptoms.

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Object: The aim of this study was to evaluate the efficacy of a treatment combination of coil embolization and clot evacuation in patients presenting with an intracerebral hematoma (ICH) caused by the rupture of an aneurysm.

Methods: Twenty-seven patients were prospectively recruited in this study between 1996 and 2000. Endovascular treatment of the putative ruptured aneurysm was performed as soon as practical after diagnosis and before surgical evacuation of the ICH.

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