A LCMT1-PME-1 methylation equilibrium controls mitotic spindle size

Leucine carboxyl methyltransferase-1 (LCMT1) and protein phosphatase methylesterase-1 (PME-1) are essential enzymes that regulate the methylation of the protein phosphatase 2A catalytic subunit (PP2AC). LCMT1 and PME-1 have been linked to the regulation of cell growth and proliferation, but the underlying mechanisms have remained elusive. We show here an important role for an LCMT1-PME-1 methylation equilibrium in controlling mitotic spindle size. Depletion of LCMT1 or overexpression of PME-1 led to long spindles. In contrast, depletion of PME-1, pharmacological inhibition of PME-1 or overexpression of LCMT1 led to short spindles. Furthermore, perturbation of the LCMT1-PME-1 methylation equilibrium led to mitotic arrest, spindle assembly checkpoint activation, defective cell divisions, induction of apoptosis and reduced cell viability. Thus, we propose that the LCMT1-PME-1 methylation equilibrium is critical for regulating mitotic spindle size and thereby proper cell division.

Proteomic Analysis of the Mammalian Katanin Family of Microtubule-severing Enzymes Defines Katanin p80 subunit B-like 1 (KATNBL1) as a Regulator of Mammalian Katanin Microtubule-severing

The Katanin family of microtubule-severing enzymes is critical for remodeling microtubule-based structures that influence cell division, motility, morphogenesis and signaling. Katanin is composed of a catalytic p60 subunit (A subunit, KATNA1) and a regulatory p80 subunit (B subunit, KATNB1). The mammalian genome also encodes two additional A-like subunits (KATNAL1 and KATNAL2) and one additional B-like subunit (KATNBL1) that have remained poorly characterized. To better understand the factors and mechanisms controlling mammalian microtubule-severing, we have taken a mass proteomic approach to define the protein interaction module for each mammalian Katanin subunit and to generate the mammalian Katanin family interaction network (Katan-ome). Further, we have analyzed the function of the KATNBL1 subunit and determined that it associates with KATNA1 and KATNAL1, it localizes to the spindle poles only during mitosis and it regulates Katanin A subunit microtubule-severing activity in vitro. Interestingly, during interphase, KATNBL1 is sequestered in the nucleus through an N-terminal nuclear localization signal. Finally KATNB1 was able to compete the interaction of KATNBL1 with KATNA1 and KATNAL1. These data indicate that KATNBL1 functions as a regulator of Katanin A subunit microtubule-severing activity during mitosis and that it likely coordinates with KATNB1 to perform this function.

HydroCoils Are Associated with Lower Angiographic Recurrence Rates Than Are Bare Platinum Coils in Treatment of "Difficult-to-Treat" Aneurysms: A Post Hoc Subgroup Analysis of the HELPS Trial

BACKGROUND AND PURPOSE

The HydroCoil Endovascular Aneurysm Occlusion and Packing Study was a randomized controlled trial that compared HydroCoils to bare platinum coils. Using data from this trial, we performed a subgroup analysis of angiographic and clinical outcomes of patients with "difficult-to-treat" aneurysms, defined as irregularly shaped and/or having a dome-to-neck ratio of <1.5.

MATERIALS AND METHODS

Separate subgroup analyses comparing outcomes of treatment with HydroCoils to that of bare platinum coils were performed for the following: 1) irregularly shaped aneurysms, 2) regularly shaped aneurysms, 3) aneurysms with a dome-to-neck ratio of <1.5, and 4) aneurysms with a dome-to-neck ratio of ≥1.5. For each subgroup analysis, the following outcomes were studied at the last follow-up (3-18 months): 1) any recurrence, 2) major recurrence, 3) re-treatment, and 4) an mRS score of ≤2. Multivariate logistic regression analysis was performed to determine if the HydroCoil was independently associated with improved outcomes in these subgroups.

RESULTS

Among the patients with an irregularly shaped aneurysm, the HydroCoil was associated with lower major recurrence rates than the bare platinum coils (17 of 66 [26%] vs 30 of 69 [44%], respectively; P = .046). Among the patients with an aneurysm with a small dome-to-neck ratio, the HydroCoil was associated with lower major recurrence rates than the bare platinum coils (18 of 73 [24.7%] vs 32 of 76 [42.1%], respectively; P = .02). No difference in major recurrence was seen between HydroCoils and bare platinum coils for regularly shaped aneurysms (42 of 152 [27.6%] vs 52 of 162 [32.1%], respectively; P = .39) or aneurysms with a large dome-to-neck ratio (41 of 145 [28.3%] vs 50 of 155 [32.3%], respectively; P = .53).

CONCLUSIONS

This unplanned post hoc subgroup analysis found that HydroCoils are associated with improved angiographic outcomes in the treatment of irregularly shaped aneurysms and aneurysms with a dome-to-neck ratio of <1.5. Because this was a post hoc analysis, these results are not reliable and absolutely should not alter clinical practice but, rather, may inform the design of future randomized controlled trials.

p16 Protein and gigaxonin are associated with the ubiquitination of NFκB in cisplatin-induced senescence of cancer cells

The molecular mechanism of p16-mediated senescence in cisplatin-treated cancer cells is not fully understood. Here we show that cisplatin treatment of head and neck cancer cells results in nuclear transport of p16 leading to a molecular modification of NFκB. Chromatin immunoprecipitation assays show that this modification is associated with the inhibition of NFκB interacting with its DNA binding sequences, leading to decreased expression of NFκB-transcribed proteins. LCMS proteomic analysis of LAP-TAP-purified proteins from HeLa cells containing a tetracycline-inducible GFP-S peptide-NFκB expression system identified gigaxonin, an ubiquitin E3 ligase adaptor, as an NFκB-interacting protein. Immunoblotting and siRNA studies confirmed the NFκB-gigaxonin interaction and the dependence of this binding on p16-NFκB binding. Using gel shift assays, we have confirmed p16-NFκB and gigaxonin-NFκB interactions. Furthermore, we have observed increased NFκB ubiquitination with cisplatin treatment that is abolished in the absence of p16 and gigaxonin expression. Analysis of 103 primary tumors has shown that increased nuclear p16 expression correlates with enhanced survival of head and neck cancer patients (p < 0.0000542), indicating the importance of nuclear p16 expression in prognosis. Finally, p16 expression is associated with reduced cytokine expression and the presence of human papilloma virus in chemoradiation-sensitive basaloid tumors. However, the absence of p16 expression is associated with enhanced cytokine expression and the absence of human papilloma virus in aggressive tumors. These results clearly demonstrate that nuclear p16 and gigaxonin play an important role in chemosensitivity of head and neck cancers through ubiquitination of NFκB.

Treatment of poor-grade subarachnoid hemorrhage trial

BACKGROUND AND PURPOSE

Management of poor-grade subarachnoid hemorrhage is based on limited evidence from small single-center retrospective observational studies. The purpose of this study was to undertake a single-center randomized controlled feasibility trial comparing a strategy of early endovascular aneurysm treatment with treatment after neurologic recovery in this group of patients.

MATERIALS AND METHODS

Patients with poor-grade SAH were randomized within 24 hours of admission to early treatment or treatment after neurologic recovery. If a patient was randomized to early treatment, the aneurysm was treated endovascularly within 24 hours of randomization. Recruitment rate, safety profile, and functional outcome at the time of discharge and at 6 months were assessed.

RESULTS

Fourteen of 51 patients screened were eligible for the trial. Of these 14, 8 patients were randomized (57%). All patients in the early coiling arm received treatment within 24 hours of randomization. There was no treatment-related complication. Overall, good outcome occurred in 25% of patients; the mortality rate was 75%. Patients in the early treatment arm (n = 5) had a good outcome rate of 20%, while those in treatment after neurologic recovery arm (n = 3) had a good outcome rate of 33.3%.

CONCLUSIONS

This was a feasibility study that demonstrated that recruitment and randomization for comparing management strategies in poor-grade SAH are feasible. The recruitment rate among eligible patients was encouraging (57%), though a number of patients had to be excluded due to ineligibility. A multicenter study is necessary to recruit the numbers required to compare the clinical outcomes of these management strategies.

Bioactive versus bare platinum coils in the treatment of intracranial aneurysms: the MAPS (Matrix and Platinum Science) trial

BACKGROUND AND PURPOSE

The ability of polymer-modified coils to promote stable aneurysm occlusion after endovascular treatment is not well-documented. Angiographic aneurysm recurrence is widely used as a surrogate for treatment failure, but studies documenting the correlation of angiographic recurrence with clinical failure are limited. This trial compares the effectiveness of Matrix(2) polyglycolic/polylactic acid biopolymer-modified coils with bare metal coils and correlates the angiographic findings with clinical failure (ie, target aneurysm recurrence), a composite end point that includes any incident of posttreatment aneurysm rupture, retreatment, or unexplained death.

MATERIALS AND METHODS

This was a multicenter randomized noninferiority trial with blinded end point adjudication. We enrolled 626 patients, divided between Matrix(2) and bare metal coil groups. The primary outcome was target aneurysm recurrence at 12 ± 3 months.

RESULTS

At 455 days, at least 1 target aneurysm recurrence event had occurred in 14.6% of patients treated with bare metal coils and 13.3% of Matrix(2) (P = .76, log-rank test) patients; 92.8% of target aneurysm recurrence events were re-interventions for aneurysms that had not bled after treatment, and 5.8% of target aneurysm recurrence events resulted from hemorrhage or rehemorrhage, with or without retreatment. Symptomatic re-intervention occurred in only 4 (0.6%) patients. At 455 days, 95.8% of patients with unruptured aneurysms and 90.4% of those with ruptured aneurysms were independent (mRS ≤ 2). Target aneurysm recurrence was associated with incomplete initial angiographic aneurysm obliteration, presentation with rupture, and a larger aneurysmal dome and neck size.

CONCLUSIONS

Tested Matrix(2) coils were not inferior to bare metal coils. Endovascular coiling of intracranial aneurysms was safe, and the rate of technical success was high. Target aneurysm recurrence is a promising clinical outcome measure that correlates well with established angiographic measurements.

Stent-assisted coiling versus coiling alone in unruptured intracranial aneurysms in the matrix and platinum science trial: safety, efficacy, and mid-term outcomes

BACKGROUND AND PURPOSE

Stent-assisted coiling may result in less aneurysm recanalization but more complications than coiling alone. We evaluated outcomes of coiling with and without stents in the multicenter Matrix and Platinum Science Trial.

MATERIALS AND METHODS

All patients in the Matrix and Platinum Science Trial with unruptured intracranial aneurysms treated per protocol were included. Baseline patient and aneurysm characteristics, procedural details, neurologic outcomes, angiographic outcomes, and safety data were analyzed.

RESULTS

Overall, 137 of 361 (38%) patients were treated with a stent. Stent-coiled aneurysms had wider necks (≥4 mm in 62% with stents versus 33% without, P < .0001) and lower dome-to-neck ratios (1.3 versus 1.8, P < .0001). Periprocedural serious adverse events occurred infrequently in those treated with and without stents (6.6% versus 4.5%, P = .39). At 1 year, total significant adverse events, mortality, and worsening of mRS were similar in treatment groups, but ischemic strokes were more common in stent-coiled patients than in coiled patients (8.8% versus 2.2%, P = .005). However, multivariate analysis confirmed that at 2 years after treatment, prior cerebrovascular accident (OR, 4.7; P = .0089) and aneurysm neck width ≥4 mm (OR, 4.5; P = .02) were the only independent predictors of ischemic stroke. Stent use was not an independent predictor of ischemic stroke at 2 years (OR, 1.1; P = .94). Stent use did not predict target aneurysm recurrence at 2 years, but aneurysm dome size ≥10 mm (OR, 9.94; P < .0001) did predict target aneurysm recurrence.

CONCLUSIONS

Stent-coiling had similar outcomes as coiling despite stented aneurysms having more difficult morphology than coiled aneurysms. Increased ischemic events in stent-coiled aneurysms were attributable to baseline risk factors and aneurysm morphology.

Endovascular stenting of the transverse sinus in a patient presenting with benign intracranial hypertension

The authors present a 37-year-old lady with symptoms and signs suggestive of benign intracranial hypertension (BIH). Routine CT and MRI scans were normal. Further investigations were performed with magnetic resonance venography (MRV) and cerebral venography. These revealed obstruction of the right transverse sinus with high pressure (40 mmHg) proximal to the obstruction and low pressure (15 mmHg) distally. She was treated by transvenous stent deployment with resolution of her symptoms and the bilateral papilloedema. Evaluation of the cerebral venous system with MRV and or with formal cerebral venography should be included in routine investigations of patients with suspected BIH.

Endovascular treatment of anterior communicating artery aneurysms: results of clinical and radiological outcome in Newcastle

The results of endovascular management of anterior communicating artery aneurysms (ACoAA) using Guglielmi Detachable Coils (GDC) are presented. We detail the clinical and radiological features, and postoperative clinical and radiological outcome in a consecutive series of patients. We have prospectively collected comprehensive data on our patients with SAH since 1989. This study reports on patients admitted between January 1990 and December 1998, and focuses on 30 patients who had their ACoAA endovascularly treated. An independent observer (TE) carried out long-term follow-up in January 2002. Statistical analysis was performed to study the relationship between clinical factors, the radiological morphology of aneurysms and the long-term outcome. The age ranged from 25 to 74 years (median: 54) and endovascularly treated ACoAA were more common in women, 19 (63%) compared with men, 11 (37%). Seventy-seven per cent were in good grade (WFNS 1 & 2) before treatment. Three patients rebled before treatment. The aneurysms were less than 10 mm in maximal diameter in 27/30 patients. The follow-up period was from 1 to 53 months (mean 32.5, median 36.6 months). Excellent outcome was recorded for 11 patients (36.7%), good in seven patients (23.3%), fair in three patients (10%) and poor in four cases (13.3%). Five patients had died (mortality 16.7%). Favourable outcome was achieved in younger patients, women, and in those who presented in grades 1 and 2. The long-term radiological follow-up revealed residual necks in 13 patients. Only one has required retreatment and no rebleed has occurred in 3-6 years. This study reports a contemporary experience with the endovascular management of ACoAA. Long-term stability of the coil and good outcome is demonstrated. Endovascular treatment using GDC is an efficient technique for treating acutely ruptured ACoAA with little additional morbidity. The clinical and radiological results are comparable with those in the literature.

Embolization of residual fistula following stereotactic radiosurgery in cerebral arteriovenous malformations

Treatment of brain arteriovenous malformations (BAVMs) often requires a multitechnique approach. We present 2 cases of BAVM, in which initial stereotactic radiosurgery (SRS) was successful in obliterating a significant volume of the nidus. At follow-up angiography, residual fistulas were identified and selectively embolized; this procedure cured the lesions. Many series describe initial embolization to reduce the nidal volume followed by SRS to the remnant. The described cases highlight the value of primary radiosurgery followed by selective fistula embolization.

Findings of the International Subarachnoid Aneurysm Trial and the National Study of Subarachnoid Haemorrhage in context

Concern has been expressed about the applicability of the findings of the International Subarachnoid Aneurysm Trial (ISAT) with respect to the relative effects on outcome of coiling and clipping. It has been suggested that the findings of the National Study of Subarachnoid Haemorrhage may have greater relevance for neurosurgical practice. The objective of this paper was to interpret the findings of these two studies in the context of differences in their study populations, design, execution and analysis. Because of differences in design and analysis, the findings of the two studies are not directly comparable. The ISAT analysed all randomized patients by intention-to-treat, including some who did not undergo a repair, and obtained the primary outcome for 99% of participants. The National Study only analysed participants who underwent clipping or coiling, according to the method of repair, and obtained the primary outcome for 91% of participants. Time to repair was also considered differently in the two studies. The comparison between coiling and clipping was susceptible to confounding in the National Study, but not in the ISAT. The two study populations differed to some extent, but inspection of these differences does not support the view that coiling was applied inappropriately in the National Study. Therefore, there are many reasons why the two studies estimated different sizes of effect. The possibility that there were real, systematic differences in practice between the ISAT and the National Study cannot be ruled out, but such explanations must be seen in the context of other explanations relating to chance, differences in design or analysis, or confounding.

HydroCoil Endovascular Aneurysm Occlusion and Packing Study (HELPS trial): procedural safety and operator-assessed efficacy results

BACKGROUND AND PURPOSE

Coated coils have been in clinical use for several years without robust evidence to determine their safety/efficacy. The HydroCoil Endovascular Aneurysm Occlusion and Packing Study (HELPS) addresses this deficiency for the HydroCoil embolic system. This article reports periprocedural safety/operator-assessed angiographic results from HELPS.

MATERIALS AND METHODS

Patients were randomized to the hydrogel coil or control arms by using concealed allocation with minimization matching groups. Any bare platinum coils were allowed in the control arm, and assist devices could be used as clinically required. Both recently ruptured and not recently ruptured/unruptured aneurysms were included. Analysis was on an intention-to-treat basis.

RESULTS

Four hundred ninety-nine patients were recruited. Coiling was successful in 98.6%. Mean aneurysm size was 6.5 mm (26% were > or =10 mm), 53% were recently ruptured aneurysms, and an assist device was used in 46%. Seventy procedural adverse events were reported in hydrogel coils and 86 in control arms. The 3-month mortality rate was 3.6% in hydrogel coils and 2.0% in control arms; the difference was not significant (P = .6). There was a lower 2-month mortality rate in the HELPS subarachnoid hemorrhage cohort (4.1%) than would be anticipated from the International Subarachnoid Aneurysm Trial (7%). There was a trend toward increased adverse events when assist devices were used, which was substantial for stents deployed in recently ruptured aneurysms. Ninety-six percent of patients discharged were World Federation of Neurosurgeons grade 0-2 at discharge. No difference was found between arms in the operator assessment of angiographic occlusions (P = .3).

CONCLUSION

These HELPS results reinforce coiling as an effective treatment for aneurysms, with an excellent technical success rate. Hydrogel coils can be used in a wide spectrum of aneurysms with a risk profile equivalent to that of bare platinum.

Single-center experience of cerecyte coils in the treatment of intracranial aneurysms: initial experience and early follow-up results

BACKGROUND AND PURPOSE

Endovascular treatment of intracranial aneurysms using platinum coils is effective, but uncommonly aneurysms recur. New-generation coils, such as Cerecyte, aim to address this problem. This study examines the safety and efficacy of these coils in the treatment of a cohort of ruptured and unruptured aneurysms

MATERIALS AND METHODS

Sixty-seven patients with 68 aneurysms were included in the study. Of these, 51 were treated exclusively with the new polyglycolic acid (PGA)-containing coils, and 17 were treated with a combination of new PGA-containing and other coils. Initial and follow-up angiograms were graded according to the 3-point scale of occlusion. Follow-up angiography was available in 46 cases at 6 months. Based on occlusion grading at initial and follow-up angiography, aneurysms were classified into stable, improved, and worsened (recanalized) groups.

RESULTS

Of the exclusive new-coil cohort, 36 cases (70.6%) were initially completely occluded (grade 1), 12 (23.5%) showed filling at the neck (grade 2), and 3 (5.9%) showed contrast within the neck and sac (grade 3). Analysis of the follow-up angiograms showed 24 (70.6%) had stable occlusion, 3 (8.8%) had improved occlusion, and 7 (20.6%) had worsening occlusion. Data for cases treated with new PGA-containing coils together with bare platinum coils were also analyzed separately. Intraprocedural adverse events were noted in 4 cases (7.8%), but there were no clinical sequelae. There were no rebleeds in the follow-up period.

CONCLUSION

New PGA-containing coils show no excess in procedural and periprocedural complications over bare platinum coils, and the recanalization rate is comparable with bare platinum coils in the short term.

Follow-up of intracranial aneurysms treated with matrix detachable coils: a single-center experience

BACKGROUND AND PURPOSE

Matrix coils are polymer-coated bioactive coils used in treatment of intracranial aneurysms. The current study is aimed at evaluating the efficacy and safety of these coils in treatment of ruptured and unruptured aneurysms.

METHODS

Seventy-seven consecutive patients with 84 aneurysms were included in the study. Forty-six aneurysms were treated with Matrix coils alone, and 38 were treated with Matrix coils in combination with other coils/devices. Angiographic follow-up was available in 64 patients with 70 aneurysms. Length of follow-up ranged from 6 to 28 months with mean of 10 months. Both postembolization and follow-up angiograms were graded on a 3-point Raymond scale. Aneurysms were classified as stable, improved, or recanalized based on the follow-up angiograms. Recanalization was considered major if it was saccular and its size would theoretically permit retreatment with coils.

RESULTS

At the end of the initial procedure, 47 (56.0%) aneurysms showed complete occlusion (Raymond 1), 20 (23.8%) showed contrast filling the neck of the aneurysm (Raymond 2), and 16 (19.0%) showed contrast filling the sac of the aneurysm (Raymond 3). Of the 70 aneurysms in which follow-up angiograms were available, 55.7% remained stable in appearance, 20.0% showed improved occlusion, and 24.3% demonstrated recanalization; 8.6% demonstrated major recanalization. There were 2 aneurysm rebleeds (both incompletely packed); one resulted in death.

CONCLUSION

Matrix coils are safe to use and the recanalization rate of aneurysms treated with these coils appears to be at least comparable with historical studies with Guglielmi detachable coils.

Temporary alopecia after subarachnoid haemorrhage

Primary endovascular intervention is increasingly the first choice of treatment for cerebral aneurysms, particularly for those with complex anatomy in the posterior circulation. However, their clinical management and follow-up continue to be predominantly in the hands of neurosurgeons. In this report, the development of alopecia following the coiling of posterior circulation aneurysms is described. The alopecia was transient and lasted for approximately 6 months, and occurred in the occipital and suboccipital regions of the scalp. This report aims to highlight this condition, which has not been previously reported in the neurosurgical literature. The potential hazards of irradiation should be borne in mind while carrying out complex endovascular procedures. The patient should be counselled and all necessary steps undertaken to limit radiation exposure.

Comparison of image quality, diagnostic confidence and interobserver variability in contrast enhanced MR angiography and 2D time of flight angiography in evaluation of carotid stenosis

The aim of this study was to compare image quality, level of diagnostic confidence and interobserver agreement in assessment of carotid stenosis with contrast enhanced MR angiography (CE MRA) in comparison with 2D time of flight MR angiography (2D TOF MRA). 60 carotid arteries in 30 patients were examined by three observers. Image quality and diagnostic confidence were assessed on the basis of a visual analogue scale. Interobserver variability was assessed with the help of intraclass correlation coefficient. Median values on the visual analogue scale for image quality and diagnostic confidence were higher for CE MRA compared with 2D TOF MRA for all three observers. Higher intraclass correlation values were recorded for interobserver variability for CE MRA compared with 2D TOF MRA both for visual estimation of carotid stenosis as well as for measurement of carotid stenosis on the basis of North American Symptomatic Carotid Endarterectomy Trial (NASCET) and European Carotid Surgery Trial (ECST) criteria. CE MRA provides better image quality, higher level of diagnostic confidence and more interobserver agreement compared with 2D TOF MRA.

Alexander disease: Ventricular garlands and abnormalities of the medulla and spinal cord

BACKGROUND

Alexander disease is most commonly associated with macrocephaly and, on MRI, a leukoencephalopathy with frontal preponderance. The disease is caused by mutation of the GFAP gene. Clinical and MRI phenotypic variation have been increasingly recognized.

METHODS

The authors studied seven patients with Alexander disease, diagnosed based on mutations in the GFAP gene, who presented unusual MRI findings. The authors reviewed clinical history, MRI abnormalities, and GFAP mutations.

RESULTS

All patients had juvenile disease onset with signs of brainstem or spinal cord dysfunction. None of the patients had a macrocephaly. The MRI abnormalities were dominated by medulla and spinal cord abnormalities, either signal abnormalities or atrophy. One patient had only minor cerebral white matter abnormalities. A peculiar finding was the presence of a kind of garland along the ventricular wall in four patients. Three patients had an unusual GFAP mutation, one of which was a duplication mutation of two amino acids, and one an insertion deletion.

CONCLUSION

Signal abnormalities or atrophy of the medulla or spinal cord on MRI are sufficient to warrant DNA analysis for Alexander disease. Ventricular garlands constitute a new sign of the disease. Unusual phenotypes of Alexander disease are found among patients with late onset and protracted disease course.

Use of neuroform stent in a patient with acute stroke caused by spontaneous petrous segment internal carotid artery dissection: a case report

SUMMARY

Neuroform stents have been recently introduced for treatment of broad-necked intracranial aneurysms. Several studies have demonstrated the feasibility of deployment of Neuroform stents (Boston Scientific Target, USA) in intracranial circulation. We report a case of a patient presenting with acute stroke due to occlusive petrous segment internal carotid artery dissection who was treated with a Neuroform stent.

Does the method of treatment of acutely ruptured intracranial aneurysms influence the incidence and duration of cerebral vasospasm and clinical outcome?

OBJECTIVES

Cerebral vasospasm remains the leading cause of death and permanent disability after subarachnoid haemorrhage. This study determined whether the method of aneurysm treatment plays an important role in determining the incidence of cerebral vasospasm and its clinical consequences.

METHODS

Admission data, cranial computed tomography (CT), treatment details, transcranial Doppler (TCD) results, and clinical outcomes of patients who had surgical or endovascular management of their ruptured aneurysm were recorded and subject to multivariate analysis.

RESULTS

Between January 1995 and December 1999, 292 eligible patients (206 female, 86 male) had definitive aneurysm treatment at our unit. 212 patients were clipped, 80 coiled. There was no significant difference in patient age, pre-treatment neurological grade, Fisher grade, or timing of treatment in the two groups. 48.3% patients developed TCD detected cerebral vasospasm and 16.1% patients developed permanent ischaemic neurological deficit. At clinical follow up, 84.2% of patients were well (mGOS 1 and 2) with a cumulative death rate of 6.5% from all causes. The only significant predictor of TCD-detected cerebral vasospasm was patient age (inversely, p = 0.004). Increased patient age, vasospasm, poor pre-treatment WFNS, and higher CT Fisher grades correlated with a poor discharge GOS. However, only poor pre-treatment WFNS grade and patient age correlated with poor GOS at follow up (p<0.001).

CONCLUSION

The treatment method had no influence on the incidence or duration of TCD detected vasospasm and there was no significant difference in outcome at discharge or follow up between those patients who had surgery or endovascular management of their aneurysms.

Cerebral edema associated with betaine treatment in classical homocystinuria

A child with cystathionine beta-synthase deficiency developed cerebral edema 4 to 6 weeks after starting betaine therapy. There was no evidence of intracranial thrombosis, but there was widespread edema of the white matter. He recovered fully after emergency decompressive craniotomy and withdrawal of betaine.

Atrophy of the putamen in dementia with Lewy bodies but not Alzheimer's disease: an MRI study

OBJECTIVE

To compare the volume of the putamen on MRI in subjects with Alzheimer's disease (AD) and dementia with Lewy bodies (DLB) and age-matched normal control subjects, along with the relationship between putamen volume and severity of both extrapyramidal signs and cognitive impairment.

METHODS

MRI-based volumetric measurements at 1.5 T of total intracranial volume, total brain volume, and putamen volume were acquired in elderly patients with AD (n = 27; 77.6 years) and DLB (n = 14; 76.2 years) and normal control subjects (n = 37; 75.4 years). Patients and control subjects also underwent a standardized neuropsychiatric examination including the motor subsection of the Unified Parkinson's Disease Rating Scale (UPDRS III) and the Cambridge Cognitive Examination (CAMCOG) with Mini-Mental State Examination (MMSE).

RESULTS

Patients with DLB had smaller raw putamen volumes than control subjects (right 12.5% reduction, p = 0.007; left 13.7% reduction, p = 0.003). When putamen volume was normalized to total intracranial volume, patients with DLB had significantly smaller volume ratios than both controls and patients with AD. Patients with AD did not differ from control subjects on any measure of putamen volume. Putamen volume did not correlate with age or with scores on UPDRS III, CAMCOG, or MMSE in any of the groups.

CONCLUSIONS

Atrophy of the putamen is a feature of DLB. This may be important in understanding the etiology of parkinsonian features seen in DLB, though in this study, no direct correlation was found between degree of volume loss and severity of parkinsonism.

Endovascular management of unruptured intracranial aneurysms: does outcome justify treatment?

OBJECTIVE

The appropriate management of unruptured intracranial aneurysms depends on a complete understanding of their natural history and on the risks and efficacy of treatment options. There is little current data on the risks of endovascular therapy for these aneurysms. The aim of this study was to assess outcome of endovascular treatment of unruptured intracranial aneurysms.

METHOD

A retrospective analysis was performed on all unruptured aneurysms treated by Guglielmi detachable (GD) coils at this institution from 1994 to 2000.

RESULTS

Seventy three unruptured aneurysms were treated in 62 patients. There were 52 female and 10 male patients, with a median age of 55.7 years. Clinical background was: subarachnoid haemorrhage due to rupture of an additional aneurysm (40), headache (4), third nerve palsy (four), familial (four), and incidental (10). There were 14 technical failures with no clinical sequelae. Four procedural complications occurred (5.5%, 95% confidence interval (95% CI) 0.3% to 10.9%). One patient had temporary clinical sequelae (1.4%, 95% CI 0% to 2.7%); 79% of treated aneurysms had stable occlusions at follow up, 10.5% showed improved occlusion grade, 10.5% showed some recurrence, and three patients have required retreatment. Follow up modified Glasgow outcome scores were grade 1, 71%; grade 2, 18%; grade 3, 3%; grade 4, 3%. There were no deaths or haemorrhages during the follow up period. Two patients died as a result of complications from subarachnoid haemorrhage.

CONCLUSION

The endovascular treatment of patients with unruptured aneurysms is safe with few clinical or procedural complications. Poor outcomes were only seen in those patients who presented with subarachnoid haemorrhage due to rupture of an aneurysm at another site.

Tethering of the vertebral artery in the congenital arcuate foramen of the atlas vertebra: a possible cause of vertebral artery dissection in children

Twelve children with vertebrobasilar artery stroke are reported (seven males, five females; aged 6 months to 15 years). Patient 1 showed an arcuate foramen in the posterior arch of the atlas, an anatomical variant occurring in 3 to 15% of the population. It was hypothesized that the presence of the arcuate foramen might cause tethering of the vertebral artery and lead to its dissection by repetitive trauma. Lateral plain films of the cervical spine in cases of posterior circulation stroke were taken. Eight of 11 patients showed aberrant arcuate foramina. Of the remaining three patients, one had normal cervical spine X-rays, one had an absent right posterior arch of the atlas following previous surgery for a cervical meningocele, and one patient had incomplete ossification of the vertebrae. Seven of the nine patients with arcuate foramina had vertebral angiograms. In all cases this showed the vertebral artery passing through the arcuate foramen before entering the brain and an appearance consistent with arterial dissection and occlusion at the same site below the foramen. Most documented cases of posterior circulation stroke in children follow trauma, which may be minimal or repetitive, with thrombotic occlusion of the artery at C1-C2 level. The association with an arcuate foramen and its possible causative role in the genesis of posterior circulation stroke in children has not been previously recognized. There may be a causal association between the presence of an arcuate foramen, tethering of the vertebral artery in the foramen, and dissection from repetitive trauma with movement of the neck.

Endovascular approach to treatment of indirect carotico-cavernous fistulae

The purpose of the study was to assess the cure rate in patients with indirect carotico-cavernous fistula (CCF) treated by transvenous embolisation via the inferior petrosal sinus (IPS) pathway or the superior ophthalmic vein (SOV). Twelve fistulae in 11 patients were treated by transvenous embolisation, eight patients via the IPS and four fistulae in three patients via the SOV. Angiographic cure was defined as complete obliteration of the fistula and clinical cure as total resolution of signs and symptoms. Complete cure was achieved in eight patients with nine fistulae embolised transvenously. Five fistulae were approached via the IPS and four via the SOV. Our preferred method for treatment of indirect CCF is the transvenous route. The IPS approach is technically easier and has fewer potential risks than the SOV approach. However, if the IPS is not patent the SOV can provide good alternative access to the cavernous sinus.

Progressive brain atrophy on serial MRI in dementia with Lewy bodies, AD, and vascular dementia

The authors determined rates of brain atrophy, as assessed by the boundary shift integral on serial MRI, in patients with dementia with Lewy Bodies (DLB, n = 10), AD (n = 9), vascular dementia (VaD, n = 9), and age-matched controls (n = 20). Mean % +/- SD atrophy rates per year were as follows: DLB, 1.4 +/- 1.1; AD, 2.0 +/- 0.9; VaD, 1.9 +/- 1.1; and controls, 0.5 +/- 0.7. Dementia subjects had higher rates than controls (p < 0.001), but there were no significant differences between the three dementia groups. The authors found accelerating atrophy with increasing severity of cognitive impairment, further emphasizing the need for early diagnosis and intervention in dementia.

A comparison of medial and lateral temporal lobe atrophy in dementia with Lewy bodies and Alzheimer's disease: magnetic resonance imaging volumetric study

OBJECTIVES

To compare medial and lateral temporal lobe atrophy on magnetic resonance imaging (MRI) in dementia with Lewy bodies (DLB) and Alzheimer's disease (AD), and to examine the relationship between volumetric indices and cognitive and non-cognitive symptoms.

METHODS

T(1)-weighted 1.0-tesla MRI scans were acquired in elderly subjects with DLB (n = 26; mean age = 75.8 years) and AD (n = 22; 77.3 years) and normal controls (n = 26; 76.2 years). MRI-based volume measurements of the hippocampus, parahippocampus, fusiform gyrus, combined inferior and middle temporal gyri, and superior temporal gyrus were acquired.

RESULTS

Hippocampal and parahippocampal volumes were significantly larger in subjects with DLB compared to AD. Differences in hippocampal volumes between DLB and AD were observed across the entire length, and in all subjects with dementia there was a loss of hippocampal asymmetry compared to normal controls. Atrophy of temporal lobe structures correlated with memory impairment in both groups, and with age in DLB. There was no association between atrophy and psychotic symptoms in either group.

CONCLUSIONS

Subjects with DLB and AD have a different pattern of temporal lobe atrophy with the most striking differences relating to medial rather than lateral temporal lobe structures. These structural differences could explain the relative preservation of memory function in DLB compared to AD.

MRI volumetric correlates of white matter lesions in dementia with Lewy bodies and Alzheimer's disease

The aim of the study was to examine the relationship between white matter changes on magnetic resonance imaging (MRI), brain atrophy and ventricular dilation in late-life dementias. T(1)-weighted, T(2)-weighted, and proton density MRI scans were acquired in subjects with Alzheimer's disease (AD, N=25) and dementia with Lewy bodies (DLB, N=27). Total brain and ventricular volumes were measured and white matter lesions rated using a semi-quantitative scale. Periventricular hyperintensities (PVH) were found to independently correlate with advancing age and increasing ventricular dilatation in all subjects. In contrast, deep white matter hyperintensities (DWMH) did not correlate with measures of brain atrophy, ventricular dilatation or age, but were associated with a history of hypertension. These findings support the hypothesis that PVH and DWMH are pathologically diverse and that white matter change in AD and DLB may be determined by similar processes. In particular, PVH appear to be linked to atrophic processes involving ventricular enlargement and DWMH to ischaemic risk factors.

The association between white matter lesions on magnetic resonance imaging and noncognitive symptoms

A number of studies have suggested that cerebral changes, particularly deep white matter lesions (WML) visualized on magnetic resonance imaging (MRI), may be involved in the genesis of late life depression. This has been confirmed in a prospective study which also found a relationship between the presence of WML and poor 3-year outcome in elderly depressed subjects. Most studies find these lesions to predominate in frontal lobe and basal ganglia, supporting the hypothesis of "fronto-striatal" dysfunction in depression. To investigate whether WML are associated with mood disturbance in dementia, proton density and T2-weighted images were obtained in 80 subjects with dementia (dementia with Lewy bodies, n = 27; Alzheimer's disease, n = 28; vascular dementia, n = 25) and 26 age-matched normal controls. Periventricular lesions (PVL), white matter lesions (WML), and basal ganglia hyperintensities (BG) were visually rated blind to diagnosis using a semiquantitative scale. Frontal WML were associated with higher depression scores in patients with dementia, implying a common pathophysiology of depression irrespective of diagnosis. Further study of the neurobiological basis of WML is needed. This can best be achieved by serial clinical assessment combined with in vivo and in vitro MRI and neuropathological examination.

MRI volumetric study of dementia with Lewy bodies: a comparison with AD and vascular dementia

OBJECTIVE

To compare global and regional atrophy on MRI in subjects with dementia with Lewy bodies (DLB), AD, vascular dementia (VaD), and normal aging. In addition, the relationship between APOE-epsilon4 genotype and volumetric indices was examined.

METHOD

MRI-based volume measurements of the whole-brain, ventricles, frontal lobe, temporal lobe, hippocampus, and amygdala were acquired in elderly subjects with DLB (n = 27; mean age = 75.9 years), AD (n = 25; 77.2 years), VaD (n = 24; 76.9 years), and normal control subjects (n = 26; 76.2 years).

RESULTS

Subjects with DLB had significantly larger temporal lobe, hippocampal, and amygdala volumes than those with AD. No significant volumetric difference between subjects with DLB and VaD was observed. Compared with control subjects, ventricular volumes were increased in all patients with dementia, though those with DLB showed a relative preservation of whole-brain volume. There were no significant differences in frontal lobe volumes between the four groups. APOE-epsilon4 status was not associated with volumetric indices.

CONCLUSION

The findings support the hypothesis that DLB is associated with a relative preservation of temporal lobe structures. In the differentiation of DLB and AD, this may have important implications for diagnosis.

Medial temporal lobe width on CT scanning in Alzheimer's disease: comparison with vascular dementia, depression and dementia with Lewy bodies

A simple linear measurement of the minimum width of the medial temporal lobe (MTL) on angled CT scans has been suggested as an accurate ante-mortem marker for Alzheimer's disease (AD). To determine the clinical utility and specificity of this finding, we performed angled CT scans with 5-mm slices in 116 subjects referred to a geographically based Old Age Psychiatry service in Newcastle. Diagnoses were of NINCDS/ADRDA AD (n = 69, 36 probable and 33 possible). NINDS/AIREN vascular dementia (VaD, n = 25), consensus criteria for dementia with Lewy bodies (DLB, n = 9) and DSM-IV criteria for major depression (n = 13). Subjects were well matched for age. Minimum MTL width was significantly greater in depressed subjects (13.7 mm) compared to those with dementia, though no differences were seen within the dementia groups (AD 10.8, VaD 10.4, and DLB 10.9 mm). An MTL width below 11.5 mm had a sensitivity of 54% (56/103) and a specificity of 77% (10/13) for distinguishing dementia from depression. We conclude that a single cross-sectional measurement of MTL width on CT does not help differentiate between different types of dementia, though it may provide some supportive evidence when distinguishing depression from dementia.

The appearance on MRI of vertebrae in acute compression of the spinal cord due to metastases

We studied MR images of the spine in a consecutive series of 100 patients with acute compression of the spinal cord due to metastases. All patients had documented neurological deficit and histologically proven carcinoma. MRI was used to localise bony metastatic involvement and soft-tissue impingement of the cord. A systematic method of documenting metastatic involvement is described.

A total of 43 patients had compression at multiple levels; 160 vertebral levels were studied. In 120 vertebrae (75%), anterior, lateral and posterior bony elements were involved. Soft-tissue impingement of the spinal cord often involved more than one quadrant of its circumference. In 69 vertebrae (43%) there was concomitant anterior and posterior compression. Isolated involvement of a vertebral body was observed in only six vertebrae (3.8%).

We have shown that in most cases of acute compression of the spinal cord due to metastases there is coexisting involvement of both anterior and posterior structures.

The appearance on MRI of vertebrae in acute compression of the spinal cord due to metastases

We studied MR images of the spine in a consecutive series of 100 patients with acute compression of the spinal cord due to metastases. All patients had documented neurological deficit and histologically proven carcinoma. MRI was used to localise bony metastatic involvement and soft-tissue impingement of the cord. A systematic method of documenting metastatic involvement is described. A total of 43 patients had compression at multiple levels; 160 vertebral levels were studied. In 120 vertebrae (75%), anterior, lateral and posterior bony elements were involved. Soft-tissue impingement of the spinal cord often involved more than one quadrant of its circumference. In 69 vertebrae (43%) there was concomitant anterior and posterior compression. Isolated involvement of a vertebral body was observed in only six vertebrae (3.8%). We have shown that in most cases of acute compression of the spinal cord due to metastases there is coexisting involvement of both anterior and posterior structures.

Apolipoprotein E epsilon4 allele, temporal lobe atrophy, and white matter lesions in late-life dementias

OBJECTIVE

To examine the relationship between the apolipoprotein E (APOE) epsilon4 genotype, medial temporal lobe atrophy, and white matter hyperintensities on magnetic resonance imaging in late-life dementias.

DESIGN

Structural magnetic resonance imaging study using T2-weighted and proton density-weighted axial scans and T1-weighted coronal scans.

SETTING

Community-dwelling population of elderly patients prospectively chosen from a clinical case register of consecutive referrals to old age psychiatry services.

SUBJECTS

Twenty-five subjects with Alzheimer disease (by criteria of the National Institute of Neurological and Communication Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association; mean age, 77.8 years), 22 subjects with dementia with Lewy bodies (consensus criteria; mean age, 77.2 years), and 24 subjects with vascular dementia (by criteria of the National Institute of Neurological Disorders and Stroke and the Association International pour la Recherche et l'Enseignement en Neurosciences; mean age, 76.9 years) were selected. Subjects were well matched for age, sex, duration of illness, and cognitive function.

MAIN OUTCOME MEASURES

The APOE genotype was determined using the polymerase chain reaction method, and medial temporal lobe atrophy and white matter hyperintensities (periventricular and deep white matter) were visually rated using standardized scales.

RESULTS

In all subjects with dementia, no significant associations were noted between APOE epsilon4 status and medial temporal lobe atrophy (mean score: 0 epsilon4 = 4.5, 1 epsilon4 = 4.5, and 2 epsilon4 = 4.3; P = .90), periventricular hyperintensities (0 epsilon4 = 3.3, 1 epsilon4 = 3.1, and 2 epsilon4 = 2.9; P = .83), and white matter hyperintensities (0 epsilon4 = 5.3, 1 epsilon4 = 4.9, and 2 epsilon4 = 4.9; P = .79).

CONCLUSIONS

The APOE epsilon4 allele does not determine medial temporal lobe atrophy or white matter lesions, as measured by magnetic resonance imaging in patients with Alzheimer disease, vascular dementia, or dementia with Lewy bodies. Although APOE epsilon4 may modify the risk for acquiring dementia, this finding provides further evidence that APOE epsilon4 does not influence pathological processes thereafter.

White matter lesions on magnetic resonance imaging in dementia with Lewy bodies, Alzheimer's disease, vascular dementia, and normal aging

OBJECTIVES

Alzheimer's disease and vascular dementia are associated with an increase in changes in white matter on MRI. The aims were to investigate whether white matter changes also occur in dementia with Lewy bodies and to examine the relation between white matter lesions and the cognitive and non-cognitive features of dementia with Lewy bodies, Alzheimer's disease, and vascular dementia.

METHODS

Proton density and T2 weighted images were obtained on a 1.0 Tesla MRI scanner in patients with dementia with Lewy bodies (consensus criteria; n=27, mean age=75.9 years), Alzheimer's disease (NINCDS/ADRDA; n=28, mean age=77.4 years), vascular dementia (NINDS/AIREN; n=25, mean age=76.8 years), and normal controls (n=26, mean age=76.2 years). Cognitive function, depressive symptoms, and psychotic features were assessed using a standardised protocol. Periventricular hyperintensities (PVHs), white matter hyperintensities (WMHs) and basal ganglia hyperintensities (BGHs) were visually rated blind to diagnosis using a semiquantitative scale.

RESULTS

Periventricular hyperintensities were positively correlated with age and were more severe in all dementia groups than controls. Total deep hyperintensities scores (WMHs plus BGHs) were significantly higher in all dementia groups than controls and higher in patients with vascular dementia than those with dementia with Lewy bodies or Alzheimer's disease. In all patients with dementia, frontal WMHs were associated with higher depression scores and occipital WMHs were associated with an absence of visual hallucinations and delusions.

CONCLUSION

In common with Alzheimer's disease and vascular dementia, PVHs and WMHs were significantly more extensive in dementia with Lewy bodies than in controls. This overlap between different dementias may reflect shared pathological mechanisms. The link between frontal WMHs and depression and the absence of occipital WMHs and psychotic symptoms has important implications for understanding the neurobiological basis of these symptoms.

Medial temporal lobe atrophy on MRI in dementia with Lewy bodies

OBJECTIVE

To investigate whether medial temporal lobe atrophy (MTA) on MRI is less frequent in dementia with Lewy bodies (DLB) compared with AD and vascular dementia (VaD), and to determine the diagnostic utility of MTA in the differential diagnosis of dementia.

METHOD

Coronal T1-weighted 1.0-T MR images were acquired in patients with DLB (consensus criteria; n = 26; mean age, 75.9 years), AD (National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association; n = 28; mean age, 77.4 years), VaD (National Institute of Neurological Disorders and Stroke-Association Internationale pour la Recherche et l'Enseignement en Neurosciences; n = 24; mean age, 76.9 years), and normal control subjects (n = 26; mean age, 76.2 years). Cognitive function was assessed using the Cambridge Cognitive Examination (CAMCOG), and MTA was rated visually using a standardized scale.

RESULTS

MTA was more frequent and severe in all dementia groups compared with control subjects (AD, 100%; VaD, 88%; DLB, 62%; control subjects, 4%; p < 0.001). Comparing dementia groups, MTA scores were significantly lower in DLB than AD (p = 0.002), with a trend toward less atrophy in DLB compared with VaD (p = 0.07). The absence of MTA had a specificity of 100% and 88% for separating DLB from AD and VaD respectively, and a sensitivity of 38%. In patients with DLB, MTA increased with age (r = 0.58, p = 0.002), and in all dementia patients MTA correlated with memory impairment (combined memory score, r = -0.34, p = 0.003) but not total CAMCOG score or other subscales.

CONCLUSION

Patients with DLB have significantly greater MTA than control subjects but significantly less than those with AD. The authors confirmed that the presence of MTA is useful in detecting AD but less useful in differentiating between dementias. However, in the differentiation of DLB from AD and VaD, the absence of MTA is highly suggestive of a diagnosis of DLB.

Magnetic resonance imaging differences between dementia with Lewy bodies and Alzheimer's disease: a pilot study

BACKGROUND

Temporal lobe atrophy on magnetic resonance imaging (MRI) has been suggested as a specific diagnostic marker for Alzheimer's disease (AD). No previous comparison with dementia with Lewy bodies (DLB) has been reported.

METHOD

T1-weighted MRI scans were performed on 11 subjects with AD (nine with NINCDS/ADRDA probable AD and two with neuropathologically proven AD) and nine subjects with DLB (four with probable DLB diagnosed by clinical criteria and five with neuropathologically proven DLB). Groups were matched for age, duration of illness and cognitive test score. Two raters, blind to diagnosis and neuropathological findings, measured the volumes of the frontal lobes, temporal lobes, hippocampi, parahippocampal gyri, amygdalae, and caudate nuclei using a computerized volumetric analysis system. Scans were also rated for medial temporal atrophy on a four-point scale by an experienced rater.

RESULTS

AD subjects had significantly smaller left temporal lobes and parahippocampal gyri than those with DLB. Medial temporal atrophy was present in 9/11 AD cases (82%) and absent in 6/9 (67%) of DLB cases. Two neuropathologically confirmed cases of DLB had severe medial temporal atrophy; both had concurrent AD-type pathology in the temporal lobe (Braak stage 4).

CONCLUSIONS

This pilot study supports the hypothesis that a greater burden of pathology centres on the temporal lobes in AD compared with DLB, except in DLB cases with concurrent Alzheimer pathology. A larger study is needed to confirm these findings and to determine whether MRI has a role in assisting with the clinical differentiation between DLB and AD.

Phase I study of temozolomide in paediatric patients with advanced cancer. United Kingdom Children's Cancer Study Group

A phase I study of temozolomide administered orally once a day, on 5 consecutive days, between 500 and 1200 mg m(-2) per 28-day cycle was performed. Children were stratified according to prior craniospinal irradiation or nitrosourea therapy. Sixteen of 20 patients who had not received prior craniospinal irradiation or nitrosourea therapy were evaluable. Myelosuppression was dose limiting, with Common Toxicity Criteria (CTC) grade 4 thrombocytopenia occurring in one of six patients receiving 1000 mg m(-2) per cycle, and two of four patients treated at 1200 mg m(-2) per cycle. Therefore, the maximum-tolerated dose (MTD) was 1000 mg m(-2) per cycle. The MTD was not defined for children with prior craniospinal irradiation because of poor recruitment. Plasma pharmacokinetic analyses showed temozolomide to be rapidly absorbed and eliminated, with linear increases in peak plasma concentrations and systemic exposure with increasing dose. Responses (CR and PR) were seen in two out of five patients with high-grade astrocytomas, and one patient had stable disease. One of ten patients with diffuse intrinsic brain stem glioma achieved a long-term partial response, and a further two patients had stable disease. Therefore, the dose recommended for phase II studies in patients who have not received prior craniospinal irradiation or nitrosoureas is 1000 mg m(-2) per cycle. Further evaluation in diffuse intrinsic brain stem gliomas and other high-grade astrocytomas is warranted.