Implications of Extracranial Distortion in Ultra-High-Field Magnetic Resonance Imaging for Image-Guided Cranial Neurosurgery.

Background: Ultra-high-field magnetic resonance imaging (MRI) of the brain is attractive for image guidance during neurosurgery because of its high tissue contrast and detailed vessel visualization. However, high-field MRI is prone to distortion artifacts, which may compromise image guidance. Here we investigate intra- and extracranial distortions in 7-T MRI scans.

Prevalence of brain arteriovenous malformations in first-degree relatives of patients with a brain arteriovenous malformation.

Background And Purpose: It is uncertain whether familial occurrence of brain arteriovenous malformations (BAVMs) represents coincidental aggregation or a shared familial risk factor. We aimed to compare the prevalence of BAVMs in first-degree relatives (FDRs) of patients with BAVM and the prevalence in the general population.

Methods: We sent a postal questionnaire to 682 patients diagnosed with a BAVM in 1 of 4 university hospitals to retrieve information about the occurrence of BAVMs among their FDRs.

Prognosis of acute subdural haematoma from intracranial aneurysm rupture.

Background: Acute subdural haematoma (aSDH) is a rare complication of aneurysmal subarachnoid haemorrhage (SAH) and is associated with poor clinical condition on admission and poor outcome.

Objective: The aim of this study was to assess whether aneurysmal aSDH is an independent risk factor for poor outcome.

Methods: In a series of 1632 patients retrieved from our prospectively collected single centre SAH database and fulfilling prespecified inclusion criteria, we found 53 patients with aSDH on the initial CT scan.

Validation of exposure visualization and audible distance emission for navigated temporal bone drilling in phantoms.

Background: A neuronavigation interface with extended function as compared with current systems was developed to aid during temporal bone surgery. The interface, named EVADE, updates the prior anatomical image and visualizes the bone drilling process virtually in real-time without need for intra-operative imaging. Furthermore, EVADE continuously calculates the distance from the drill tip to segmented temporal bone critical structures (e.

Risk factors for acute subdural hematoma from intracranial aneurysm rupture.

Background: An acute subdural hematoma (aSDH) is a rare complication of aneurysmal subarachnoid hemorrhage (SAH) and is associated with poor clinical condition on admission and poor outcome. Risk factors for the development of an aSDH from aneurysmal rupture are unknown and may help our understanding of how an aSDH develops.

Objective: To identify risk factors for the development of an aSDH from intracranial aneurysm rupture.

Extent of bilateral neuronal network reorganization and functional recovery in relation to stroke severity.

Remodeling of neuronal structures and networks is believed to significantly contribute to (partial) restoration of functions after stroke. However, it has been unclear to what extent the brain reorganizes and how this correlates with functional recovery in relation to stroke severity. We applied serial resting-state functional MRI and diffusion tensor imaging together with behavioral testing to relate longitudinal modifications in functional and structural connectivity of the sensorimotor neuronal network to changes in sensorimotor function after unilateral stroke in rats.

Treatment of brain arteriovenous malformations: a systematic review and meta-analysis.

Context: Outcomes following treatment of brain arteriovenous malformations (AVMs) with microsurgery, embolization, stereotactic radiosurgery (SRS), or combinations vary greatly between studies.

Objectives: To assess rates of case fatality, long-term risk of hemorrhage, complications, and successful obliteration of brain AVMs after interventional treatment and to assess determinants of these outcomes.

Data Sources: We searched PubMed and EMBASE to March 1, 2011, and hand-searched 6 journals from January 2000 until March 2011.

MRI of bilateral sensorimotor network activation in response to direct intracortical stimulation in rats after unilateral stroke.

Reinstatement of perilesional activation and connectivity may underlie functional recovery after stroke. To measure activation responsiveness in perilesional cortex in relation to white matter integrity, we performed functional functional magnetic resonance imaging during stimulation of the contralesional cortex, together with diffusion tensor imaging, 3 and 28 days after stroke in rats. Despite disturbed sensorimotor function and abnormal callosal appearance at day 3, activation amplitudes were preserved in the perilesional sensorimotor cortex, although time-to-peak was significantly delayed.

Surgical treatment of sphenoorbital meningiomas.

Aim: To evaluate the outcome of surgery and radiotherapy in the treatment of sphenoorbital meningioma (SOM).

Method: A retrospective study of 66 consecutive cases treated with surgery for SOM with a minimum follow-up of 4 years. Clinical and radiological information were compared before and after the following surgical approaches: frontotemporal craniotomy, frontotemporal craniotomy combined with orbitozygomatic resection and extended lateral orbitotomy alone.

Natural history of spheno-orbital meningiomas.

Background: To investigate the natural history and the growth rate of spheno-orbital meningiomas (SOMs).

Methods: Ninety patients with a diagnosis of SOM were included, and patient charts and imaging were evaluated. In a subset of 32 patients, volumetric studies were performed.

A bundle approach to reduce the incidence of external ventricular and lumbar drain-related infections.

Object: An important complication of external CSF drainage is bacterial meningitis or ventriculitis, resulting in increased morbidity, mortality, and health care costs. In 2003, a high rate (37%) of probable drain-related infections was identified at the authors' hospital. A multidisciplinary working group was installed to reduce this incidence to < 10% within 1.

The impact of workflow and volumetric feedback on frameless image-guided neurosurgery.

Objective: During image-guided neurosurgery, if the surgeon is not fully orientated to the surgical position, he or she will briefly shift attention toward the visualization interface of an image guidance station, receiving only momentary "point-in-space" information. The aim of this study was to develop a novel visual interface for neuronavigation during brain tumor surgery, enabling intraoperative feedback on the entire progress of surgery relative to the anatomy of the brain and its pathology, regardless of the interval at which the surgeon chooses to look.

Methods: New software written in Java (Sun Microsystems, Inc.

Auditory feedback during frameless image-guided surgery in a phantom model and initial clinical experience.

In this study the authors measured the effect of auditory feedback during image-guided surgery (IGS) in a phantom model and in a clinical setting. In the phantom setup, advanced IGS with complementary auditory feedback was compared with results obtained with 2 routine forms of IGS, either with an on-screen image display or with image injection via a microscope. The effect was measured by means of volumetric resection assessments.

Application accuracy in frameless image-guided neurosurgery: a comparison study of three patient-to-image registration methods.

Object: The aim of this study was to compare three patient-to-image registration methods in frameless stereotaxy in terms of their application accuracy (the accuracy with which the position of a target can be determined intraoperatively). In frameless stereotaxy, imaging information is transposed to the surgical field to show the spatial position of a localizer or surgical instrument. The mathematical relationship between the image volume and the surgical working space is calculated using a rigid body transformation algorithm, based on point-pair matching or surface matching.

The analysis of intraoperative neurosurgical instrument movement using a navigation log-file.

Background: The purpose of this study was to define the technical requirements of future (tele)robotic neurosurgical systems. We aimed to analyse the movements of surgical instruments during neurosurgical procedures.

Methods: A commercially available neuronavigation system (StealthStation TREON(plus), Medtronic, USA) was used to determine the position and orientation of the surgical instrument.

Image-guided vascular neurosurgery based on three-dimensional rotational angiography. Technical note.

Three-dimensional rotational angiography is capable of exquisite visualization of cerebral blood vessels and their pathophysiology. Unfortunately, images obtained using this modality typically show a small region of interest without exterior landmarks to allow patient-to-image registration, precluding their use for neuronavigation purposes. The aim of this study was to find an alternative technique to enable 3D rotational angiography-guided vascular neurosurgery.

Neuronavigation and surgery of intracerebral tumours.

Approximately four decades after the successful clinical introduction of framebased stereotactic neurosurgery by Spiegel and Wycis, frameless stereotaxy emerged to enable more elaborate image guidance in open neurosurgical procedures. Frameless stereotaxy, or neuronavigation, relies on one of several different localizing techniques to determine the position of an operative instrument relative to the surgical field, without the need for a coordinate frame rigidly fixed to the patients' skull. Currently, most systems are based on the optical triangulation of infrared light sources fixed to the surgical instrument.

The impact of auditory feedback on neuronavigation.

Object: We aimed to develop an auditory feedback system to be used in addition to regular neuronavigation, in an attempt to improve the usefulness of the information offered by neuronavigation systems.

Instrumentation: Using a serial connection, instrument co-ordinates determined by a commercially available neuronavigation system were transferred to a laptop computer. Based on preoperative segmentation of the images, the software on the laptop computer produced an audible signal whenever the instrument moved into an area the surgeon wanted to avoid.

Hypomagnesemia after aneurysmal subarachnoid hemorrhage.

Objective: Hypomagnesemia frequently occurs in hospitalized patients, and it is associated with poor outcome. We assessed the frequency and time distribution of hypomagnesemia after aneurysmal subarachnoid hemorrhage (SAH) and its relationship to the severity of SAH, delayed cerebral ischemia (DCI), and outcome after 3 months.

Methods: Serum magnesium was measured in 107 consecutive patients admitted within 48 hours after SAH.

Orbital meningioma, the Utrecht experience.

AIMS. 1) To evaluate epidemiological data (age, gender, initial complaints, and ophthalmic findings) of a patient cohort with a primary or secondary orbital meningioma. 2) To evaluate the clinical course of these patients.

1H and 31P NMR measurement of cerebral lactate, high-energy phosphate levels, and pH in humans during voluntary hyperventilation: associated EEG, capnographic, and Doppler findings.

In order to explore the sensitivity of spatially resolved 1H and 31P NMR spectroscopy on a whole-body NMR instrument, cerebral metabolic changes in human volunteers were measured during hyperventilation provocation. During hyperventilation the flow velocity in the middle cerebral artery decreased significantly and the EEG showed a marked increase in slow activity. 1H NMR spectra revealed an increase in cerebral lactate concentration.