Bevacizumab may improve quality of life, but not overall survival in glioblastoma: an epidemiological study.

Background: The vascular endothelial growth factor antibody bevacizumab (Avastin®), received approval for the treatment of recurrent glioblastoma in many countries including the USA and Switzerland, but not the European Union, in 2009. Here, we explored the hypothesis that the approval of bevacizumab improved outcome with glioblastoma on a population level. Patients and methods: The prognostic significance of epidemiological, molecular genetic, and clinical data including treatment for glioblastoma patients diagnosed from 2010 to 2014 in the Canton of Zurich, Switzerland, was retrospectively analyzed using log-rank test and Cox proportional hazards models. Data were compared with data for the years 2005-2009. Results: In total, 310 glioblastoma patients were identified in the years 2010-2014. Median overall survival was 13.5 months for patients with known isocitrate dehydrogenase (IDH) wild-type (wt) (IDH1R132H-non-mutant) tumors (N = 248), compared with 11.3 months for IDH wt patients (P = 0.761) before (2005-2009). In the IDH wt cohort, bevacizumab use at any time increased from 19% in 2005-2009 to 49% in 2010-2014. Multivariate analysis did not identify bevacizumab exposure at any time to be associated with survival. Yet, upon the second-line treatment, baseline doses of corticosteroids were reduced by more than half in 83% of patients on bevacizumab compared with 48% of the patients treated with bevacizumab-free regimens (P = 0.007). Conclusion: This epidemiological study of a small, but clinically well-annotated patient cohort fails to support the assumption that the strong increase of bevacizumab use since 2010 improved survival in glioblastoma although clinical benefit associated with decreased steroid use may have been achieved.

Monitoring for potential residual disease activity by serum insulin-like growth factor 1 and soluble Klotho in patients with acromegaly after pituitary surgery: is there an impact of the genomic deletion of exon 3 in the growth hormone receptor (d3-GHR) gene on "safe" GH cut-off values?

BACKGROUND: Acromegaly is an illness usually defined by excessively high growth hormone (GH) and insulin like growth factor 1 (IGF-1) levels, the latter mainly reflecting GH action on the liver. IGF-1, also known as somatomedin C, mediates several actions of GH. The diagnosis and management of acromegaly is relatively straight forward, but long-term follow-up of patients can be difficult, as elevated IGF-1 levels can occur in the presence of apparently normalised GH levels and late recurrence of acromegaly may arise despite previous suppression on oral glucose tolerance testing. Data suggest this applies especially to patients in whom the GH receptor lacks exon 3. In such patients, GH may not always be a useful marker of disease, and traditional GH cut-offs may be misleading. Recent data suggest that soluble Klotho (sKlotho), besides and in addition to IGF-1, may help monitor the activity of GH-producing adenomas (presumably reflecting GH action on the kidneys) and may be a useful supplementary tool. METHODS: GHR genotyping was performed in 112 patients with acromegaly. IGF-1 and sKlotho levels were measured in the sera of patients before and after transsphenoidal surgery, with emphasis on patients judged inconclusively cured by surgery or with small residual tumour masses shortly after surgery. Patients were assessed for recurrence of acromegaly with GH levels (random or nadir during an oGTT). RESULTS: Of the 48 patients who underwent surgery between 2000 and 2009 and who had well-documented longer term follow-up at our institution, 29 had no biochemical evidence of residual disease activity after transsphenoidal surgery (marked reduction in IGF-1 and sKlotho levels, GH suppressible to <1 ng/ml) and were classified as in remission. 2 of these patients developed recurrent symptoms of acromegaly during follow-up with increasing levels of IGF-1 and sKlotho, and both patients were carriers of the d3-GHR genotype. CONCLUSIONS: Acromegalic patients with the d3-GHR polymorphism might be - for a given low postsurgical GH level - at higher risk for recurrence and may require a lower GH nadir during oGTT to be classified as in remission. Soluble Klotho could be useful in the follow-up of acromegalic patients. The question arises whether sKlotho not only reflects the activity of GH-secreting pituitary adenomas but whether Klotho (ectodomain clipping?) could also mediate selected actions of GH.

Antibiotic-impregnated versus silver-bearing external ventricular drainage catheters: preliminary results in a randomized controlled trial.

BACKGROUND: Evaluation of antibiotic-impregnated (AI) and ionized silver particle coated external ventricular drainage catheters (EVD) in patients with subarachnoid (SAH) or intracranial hemorrhage (ICH). METHODS: Between February 2011 and June 2012, 40 patients with acute hydrocephalus due to SAH, ICH or intraventricular hemorrhage were enrolled in a prospective, randomized, mono-center pilot study. Primary endpoints were defined as: number of events of cerebrospinal fluid (CSF) infections. Secondary endpoints were defined as: neurosurgical complications following the placement of the EVD, number of revisions of EVD catheters, and cost effectiveness. RESULTS: Sixty-one EVD placements in 40 patients, 32 antibiotic-coated (Bactiseal(®)), 29 silver-bearing catheters (VentriGuard(®)), have been performed. Confirmed or high suspicion of CSF infections occurred in 11 out of 61 events (confirmed infection: p = 0.71, probable infection: p = 0.90). Revisions of EVD were needed in 13 cases (22 %) due to CSF infection, dysfunction, impaired healing, or malplacement (p = 0.37). CONCLUSION: Regarding CSF infection rate and dysfunction, no statistical significant differences between the two EVD catheters Bactiseal(®) versus VentriGuard(®) were found. The silver-bearing catheter might offer a safe and cost-conscious alternative to the AI catheter.

Intraoperative high frequency ultrasound in intracerebral high-grade tumors.

PURPOSE: To demonstrate the utility of a new concept of intraoperative use of high frequency ultrasound (hfioUS) in maximizing the extent of resection (EOR) of intracerebral high-grade tumors. MATERIALS AND METHODS: 22 Patients harboring an intracerebral high-grade tumor were retrospectively included in this study (14 primary tumors, 8 metastasis). 14 of them had a perilesional edema equal or greater to lesion volume, 3 had previously received radiotherapy. Following macroscopic tumor debulking, the small (11 × 31 mm) L15 - 7io (Philips, Bothell, USA) high-frequency probe (7 - 15 MHz) was introduced into the resection cavity and its walls were meticulously scanned to search for tumor remnants. Postoperative MR scan was evaluated by a board-certified independent neuroradiologist, who assessed the EOR. RESULTS: Gross total resection was achieved in 21 patients (95.5 %). One patient had a small tumor remnant (6 × 4 × 3 mm) of a very large (80 × 60 × 74 mm) anaplastic astrocytoma, detected in the postoperative MR scan. A permanent postoperative hemiparesis was diagnosed in one patient with a metastasis in the motor area, while the other patients recovered without permanent neurological deficits from the surgery. CONCLUSION: The hfioUS probe allowed in this study a precise detection of the tumor and a detailed discrimination between normal, pathological and edematous tissue in all 22 cases.

Excessively high soluble Klotho in patients with acromegaly.

OBJECTIVES: Klotho-deficient mice develop a syndrome resembling accelerated ageing, and genetic variants of Klotho have been associated with human ageing. In humans, serum levels of soluble Klotho decrease with age and with chronic renal failure. The aim of our study was to examine the relationship between excess growth hormone (GH) and serum levels of Klotho in patients with acromegaly, a disease usually caused by a pituitary adenoma, which is associated with high phosphate levels and reduced life expectancy. PATIENTS AND DESIGN: We determined the levels of soluble Klotho, GH and insulin-like growth factor 1 (IGF-1) in serum samples from 24 consecutive patients with acromegaly (nine women/15 men, age 28-76 years) before and after transsphenoidal surgery. RESULTS: Soluble Klotho levels were excessively high at baseline (mean ± SEM, 4.2 ± 0.7 ng mL(-1) ) and correlated with GH (r = 0.64), IGF-1 (r = 0.57) and tumour size (r = 0.5). In multiple regression analysis, soluble Klotho was associated with GH after correction for age, gender and levels of creatinine and phosphate (P = 0.029). After surgery, GH and IGF-1 levels decreased in all patients (from 26.3 ± 5.2 to 2.6 ± 0.6 µg L(-1) , P <0.0001, and from 588 ± 35 to 193 ± 12 µg L(-1) , P < 0.001, 0.0001, respectively). Creatinine increased from 71 ± 3 to 80 ± 3 µmol L(-1) (P < 0.001), and phosphate decreased from 1.37 ± 0.04 to 1.06 ± 0.02 mmol L(-1) (P < 0.001). The markedly increased preoperative levels of soluble Klotho returned towards normal after surgery (0.7 ± 0.1 ng mL(-1) , P < 0.0001). CONCLUSIONS: This is the first study to show dramatically increased soluble Klotho levels in an acquired disease in humans. Reversal following tumour removal suggests a causal relation between the GH-producing adenoma and high serum Klotho concentration in acromegaly.

[Intraoperative neurophysiological monitoring improves outcome in neurosurgery]. / Intraoperatives neurophysiologisches Monitoring verbessert das Outcome in der Neurochirurgie.

Intraoperative Neurophysiological Mo-nitoring (IONM) identifies eloquent areas or nerves fibers during neurosurgical interventions and monitors their function. For several interventions IONM has become mandatory in neurosurgery. IONM increases patient safety during surgery as the risk of neurological deficits is reduced. Safer surgery reduces the time needed for the intervention and thereby reduces risk. IONM contributes to complete resection of tumors, which in turn prolongs patients' survival. Complicated surgical interventions associated with an elevated risk of neurological deficits have only become possible due to IONM. IONM comprises a variety of procedures that are selected for a particular intervention. With appropriate selection of the procedures IONM has been shown to improve neurological and functional outcome after neurosurgical interventions.

Cerebellar stem cells act as medulloblastoma-initiating cells in a mouse model and a neural stem cell signature characterizes a subset of human medulloblastomas.

Cells with stem cell properties have been isolated from various areas of the postnatal mammalian brain, most recently from the postnatal mouse cerebellum. We show here that inactivation of the tumor suppressor genes Rb and p53 in these endogenous neural stem cells induced deregulated proliferation and resistance to apoptosis in vitro. Moreover, injection of these cells into mice formed medulloblastomas. Medulloblastomas are the most common malignant brain tumors of childhood, and despite recent advances in treatment they are associated with high morbidity and mortality. They are highly heterogeneous tumors characterized by a diverse genetic make-up and expression profile as well as variable prognosis. Here, we describe a novel ontogenetic pathway of medulloblastoma that significantly contributes to understanding their heterogeneity. Experimental medulloblastomas originating from neural stem cells preferentially expressed stem cell markers Nestin, Sox2 and Sox9, which were not expressed in medulloblastomas originating from granule-cell-restricted progenitors. Furthermore, the expression of these markers identified a subset of human medulloblastomas associated with a poorer clinical outcome.

The transnasal transclival approach for clivus chordoma.

BACKGROUND: We present our experience using a standardized transnasal transclival approach (TTA) for endoscopic removal of chordomas of the clivus. PATIENTS: 13 patients with clival chordoma (CC) underwent tumor resection. Patients were operated by a surgical team consisting of a rhinosurgeon and a neurosurgeon. All patients underwent postoperative proton radiotherapy. Residual tumor was left in situations where radical removal would have entailed an increased risk of neurological deficits. RESULTS: Radical or near total removal of CC was accomplished in 12/13 patients. Intraoperative MRI (IMRI) was used in 4/13 CC patients. A watertight dural seal presented as the main challenge specifically for tumor extensions resulting in large dural defects. CONCLUSION: The TTA provides an elegant alternative to classical approaches to clival lesions especially for midline tumor locations. For large tumors iMRI is of significant help. Dural reconstruction of large defects emerged as the greatest challenge of this technique even for experienced endoscopic surgeons.

Insulin-like growth factor-I mRNA and peptide in the human anterior pituitary.

The pituitary is the central organ regulating virtually all endocrine processes, and pathologies of the pituitary cause manifold adverse effects. Because insulin-like growth factor (IGF)-I appears to be involved in tumour pathogenesis, progression, and persistence, and only few data exist on the cellular synthesis sites of IGF-I, the present study aims to create a basis for further research on pituitary adenomas by investigating the presence of IGF-I in the human pituitary using reverse transcriptase-polymerase chain reaction, in situ hybridisation, immunohistochemistry and immunocytochemistry. IGF-I was expressed in the pituitary, and gene sequence analysis revealed a sequence identical to that found in human liver. The distribution pattern of IGF-I mRNA found by in situ hybridisation corresponded to that of IGF-I peptide in immunohistochemistry. In all pituitary samples investigated, IGF-I-immunoreactivity occurred in almost all adrenocorticotrophic hormone (ACTH)-immunoreactive cells. Occasionally, an interindividually varying number of growth hormone (GH) and, infrequently, follicle-stimulating hormone and luteinising hormone cells contained IGF-I-immunoreactivity but none was detected in supporting cells. At the ultrastructural level, IGF-I-immunoreactivity was confined to secretory granules in coexistence with ACTH- or GH-immunoreactivity, respectively, indicating a concomitant release of the hormones. Thus, in humans, IGF-I appears to be a constituent in ACTH cells whereas its production in GH-producing and gonadotrophic cells may depend on the physiological status (e.g. serum IGF-I level, age or reproductive phase). It is assumed that locally produced IGF-I plays a crucial role in the regulation of endocrine cells by autocrine/paracrine mechanisms in addition to the endocrine route.

Intrasellar malignant peripheral nerve sheath tumor (MPNST).

Intracranial malignant peripheral nerve sheath tumors (MPNST) and intrasellar schwannomas are rare tumors. We describe a case of an intrasellar schwannoma with progression to a MPNST, a finding that, although very rare, extends the differential diagnosis of intrasellar lesions.

Extensive spherical amyloid deposition presenting as a pituitary tumor.

A 71-yr-old man was admitted for further evaluation and trans-sphenoidal surgery of a pituitary tumor. He complained of impotence and decreased libido over a period of about 40 yr. Thirty-eight yr ago he was treated for bilateral gynecomastia with galactorrhea. Endocrinological investigation at presentation revealed only mild hyperprolactinemia and hypogonadotropic hypogonadism. Pituitary magnetic resonance imaging (MRI) showed a tumor up to 2.5 cm in diameter with infiltration of the sphenoid sinus and right cavernous sinus. The tumor exhibited a heterogeneous hyperintense signal on T1-weighted images and hypointense signal on T2-weighted images. Standard trans-sphenoidal surgery was performed and a brownish mass was found inside the sella, which was removed. Histological examination of the mass revealed extensive spherical amyloid deposits with strongly positive immunohistochemical staining for prolactin. Therefore, a prolactinoma with extensive spherical amyloid deposition was diagnosed. Extensive spherical amyloid deposition is a rare finding in prolactin-secreting pituitary adenomas. So far, characteristic radiological findings by MRI have been described only twice. Due to characteristic MRI findings, the diagnosis of extensive intrasellar amyloid deposition can be entertained pre-operatively. Trans-sphenoidal surgical resection is essential to confirm the diagnosis histologically and because of the potential lack of tumor shrinkage under dopaminagonist therapy in this type of prolactinoma.

Dynamic changes during evacuation of a left temporal abscess in open MRI: technical case report.

We demonstrate the usefulness of "near real-time" neuro-navigation by open MRI systems for guidance of stereotactic evacuation of intracranial abscesses. A 70-year-old patient was referred to our institution with an intracranial left temporal abscess. He presented with headache, senso-motor aphasia and mild right hemiparesis. The abscess (35 x 25 mm) was stereotactically evacuated under MRI guidance, and a recurrence of a daughter abscess was again evacuated on the 9th postoperative day. "Near real-time" imaging showed an indentation of the abscess wall of 11 mm along the trajectory. A thermosensitive MRI protocol demonstrated a higher temperature around the abscess capsule than in the brain tissue more distant to the capsule, demonstrating the inflammatory process. The patient had 6 weeks of antibiotic therapy for gram-negative bacteria and was discharged with improved clinical symptoms 5 weeks after admission. Follow-up CT 2 months postoperatively showed a complete resolution of the abscess. Open MRI-guided interventions with "near real-time" imaging demonstrate the anatomical changes during an ongoing procedure and can be accommodated for enhancing the overall precision of stereotactic procedures. Thermosensitive MRI protocols are capable of revealing temperature gradients around inflammatory processes.

Interactive magnetic resonance imaging-guided management of intracranial cystic lesions by using an open magnetic resonance imaging system.

OBJECT: The authors present their experience with neurosurgical procedures requiring real-time imaging feedback such as aspiration of a cystic structure or abscess cavity, decompression of hydrocephalic ventricles, management of arachnoid cysts, and installation of permanent or temporary drainage conduits, in which interactive magnetic resonance (MR) imaging guidance was used to monitor structural alterations associated with the procedure. METHODS: Drainage of eight intraparenchymal brain abscesses in seven patients, decompression of space-occupying cystic or necrotic brain tumors in four patients, and endoscopic management of hydrocephalus associated with arachnoid cysts in three patients were performed using MR imaging-guided frameless stereotaxy in an open-configuration 0.5-tesla superconducting MR imaging system. Intraoperative MR imaging guidance provided accurate information on the course of the surgical procedure and associated intraoperative changes in tissue position, such as the degree of cyst aspiration, the presence or absence of hemorrhage or induced swelling, and changes associated with decompression of adjacent brain parenchyma and the ventricular system. No clinically significant complications were encountered in any patient. There were no targeting errors, and procedural objectives were accomplished in all cases. CONCLUSIONS: Drainage of brain abscesses, punctures of cystic or necrotic intracranial lesions with subsequent aspiration, and management of hydrocephalus can be performed safely and accurately by monitoring the procedure using real-time MR imaging to obtain immediate feedback on associated dynamic tissue changes.

Near-real-time guidance using intraoperative magnetic resonance imaging for radical evacuation of hypertensive hematomas in the basal ganglia.

OBJECTIVE: To report our preliminary clinical experience in treating patients with hypertensive hemorrhage in the basal ganglia using a minimally invasive approach facilitated by intraoperative real-time imaging of an open magnetic resonance imaging (MRI) system and a newly designed cutting suction device. METHODS: We developed an artifact-free device for use during intraoperative MRI consisting of a guiding base that locks into a burr hole, a side-cutting composite-based cannula connected to a standard aspirator, and a handpiece that allows aspiration strength to be regulated by the surgeon. Thirteen patients with hypertensive bleeding in the basal ganglia were included in the study. Outcome was evaluated by mortality, Glasgow Outcome Scale score, activities of daily living score, and Rankin score at 2 weeks and at a median of 4.2 months after the hemorrhage. RESULTS: In this group of 13 patients, complete evacuation was achieved in 8 patients (62%) and subtotal evacuation of 75 to 90% of the initial volume in 4 patients (31%); the evacuation was partial in 1 patient (8%). Vascular malformations were preoperatively excluded angiographically. There was no rebleeding during surgery or postoperatively, as demonstrated by immediate postoperative MRI and computed tomography on the 1st postoperative day. Hematomas were evacuated on median Day 4 after the hemorrhage, varying between Day 1 and Day 8; evacuation was performed on Day 21 after the hemorrhage in one patient. Twelve of the 13 patients survived during a median follow-up time of 4.2 months. Neurological function improved in 11 of the 12 patients eligible for assessment. One patient with an additional head injury died 15 days after surgery from pulmonary embolism. CONCLUSION: This study shows an excellent outcome with regard to mortality and a positive trend regarding neurological outcome for the specific group of patients with hypertensive hematomas in the basal ganglia. This minimally invasive approach is feasible in the open intraoperative MRI in combination with the cutting suction device developed in our institution. Online imaging is extremely helpful for planning, guiding, and real-time monitoring of the procedure.

A new artifact-free device for frameless, magnetic resonance imaging-guided stereotactic procedures.

OBJECTIVE: A new, artifact-free, nonobstructive device was required for planning, guiding, and performing stereotactic procedures in an open magnetic resonance imaging (MRI) system (Signa SP; General Electric, Milwaukee, WI). DESCRIPTION OF INSTRUMENTATION: We devised an MRI-compatible instrument set that was adapted to an optical triangulation system (FlashPoint System; Image Guided Technologies, Boulder, CO) and consisted of a Pathfinder for planning burr holes and trajectories and a Snapper-Stereoguide for guiding minimally invasive instruments such as biopsy cannulae, endoscopes, and laser fibers. The instruments were composed of biocompatible plastic (polyacetal). During evaluation, special attention was paid to safety, accuracy, operation times, and susceptibility artifacts of the system. RESULTS: The first 20 stereotactic procedures performed in the open MRI scanner included 15 biopsies, 1 cyst and 3 abscess evacuations, and 1 endoscopic procedure for treatment of multiseptate hydrocephalus. There were no adverse outcomes, and all biopsies were diagnostic. The frameless stereotactic system in combination with the FlashPoint System proved to be accurate, with a mean error of 1.5 mm. The biopsy devices did not cause any susceptibility artifacts. Highly vascularized structures were clearly visible and were included in the trajectory planning. With experience, the procedure time was reduced to less than 1 hour. CONCLUSION: This device was found to be quite helpful for planning and guiding stereotactic procedures in the open MRI scanner. Nearly real-time planning and monitoring of stereotactic procedures and the positional accuracy of the system make the open MRI system a definite improvement, compared with conventional stereotactic systems.

Functional evaluation using magnetic resonance imaging of the visual cortex in patients with retrochiasmatic lesions.

OBJECT: The goal of this study was to evaluate the clinical potential of combining functional magnetic resonance (fMR) imaging with conventional morphological MR imaging and to assess its usefulness for objective evaluation of visual function as part of treatment planning in patients harboring space-occupying lesions involving the posterior afferent visual system. METHODS: It was hypothesized that regional activation of the visual cortex during visual stimulation would show an asymmetric response consistent with the well-known retinotopical organization of the human visual cortex. To test this hypothesis, the pattern of regional cortical activity detected by fMR imaging during binocular repetitive photic stimulation (10 Hz) was compared with the findings of conventional visual field testing. Functional mapping of the visual cortex was performed using a noninvasive blood oxygen level-dependent MR technique in 10 patients with intraaxial and two with extraaxial lesions. Experiments involving two of the patients were unsuccessful because of motion artifacts. In all the remaining patients functional activity was demonstrated in the primary visual area that corresponded to the anatomical location of the calcarine cortex. In nine patients, the identified patterns of activation in the visual cortex were consistent with the visual field deficits (seven homonymous hemianopsias, one homonymous central scotoma, and one inferior quadrantanopsia) and with the traditional teaching of retinotopical representation. Discordance between fMR imaging and perimetric findings was observed in one case. CONCLUSIONS: These results demonstrate that fMR imaging can be performed routinely and successfully in patients with visual abnormalities as part of a conventional neuroradiological evaluation. The technique provides essential information about the function-structure relationship specific to an individual patient and holds promise not only for diagnosis and therapy planning, but also for understanding the topography and functional specialization of the human visual cortex.

Intraoperative color-coded duplex sonography for localization of a distal middle cerebral artery aneurysm: technical case report.

OBJECTIVE AND IMPORTANCE: We describe the surgical treatment of a small, distal, middle cerebral artery (MCA) aneurysm, performed using intraoperative color-coded duplex sonography for localization. CLINICAL PRESENTATION: A 55-year-old man presented with a sudden intense headache. Computed tomographic scans revealed a subarachnoid hemorrhage. Angiography demonstrated two MCA aneurysms, one arising from the proximal bifurcation of the right MCA and the other from its distal bifurcation. TECHNIQUE: On Day 1, the proximal MCA aneurysm was clipped via the standard transsylvian approach. The distal MCA aneurysm was identified with the aid of color-coded duplex sonography and was successfully clipped with minimal additional dissection of the sylvian fissure. CONCLUSION: Color-coded duplex sonography provides a two-dimensional image of the brain parenchyma and color-coded flow imaging of cerebral vessels in real time. It may be used for rapid intraoperative localization of small, distally located, cerebral aneurysms.

Target definition and trajectory optimization for interactive MR-guided biopsies of brain tumors in an open configuration MRI system.

We present an imaging strategy for planning and guiding brain biopsies in an open configuration MR system. Preprocedure imaging was performed in a 1.5-T MR system and was designed to provide, in a clinically efficient manner, high resolution anatomical and functional/physiologic information for precise definition and tissue characterization of the target, aiming at optimization of the biopsy trajectory for planning a safe and accurate procedure. The interventions were performed in a .5-T open bore magnet, and imaging was optimized to provide the imaging quality and temporal resolution necessary for performing the procedure interactively in near real time. Brain biopsies of 21 patients were performed in a 10-month period. Segmentation and surface rendering analysis of the lesions and vascular structures and dynamic MR perfusion and cortical activation studies provided an efficient and comprehensive way to appreciate the relationship of the target to surrounding vital structures, improved tissue characterization and definition of the tumor margins, and demonstrated the location of essential cortex, allowing appropriate placement of the burr hole and choice of optimal trajectory. Interactive protocols provided good visualization of the target and the interventional devices and offered the operator real-time feedback and control of the procedure. No complications were encountered. Advanced methods of image acquisition and processing for accurate planning of interventional brain procedures and interactive imaging with MR guidance render feasible the performance of safe and accurate neurointerventional procedures.