Arya Nabavi

Glioblastoma: Clinical characteristics, prognostic factors and survival in 492 patients

OBJECTIVE Glioblastoma is the most common and most malignant primary brain tumor in adults. The only overall accepted independent prognostic factors are patient age and performance. We present a large single institution patient series examined for prognostic factors using uni- and multivariate survival analysis. METHODS 492 patients were included who underwent craniotomy for newly diagnosed glioblastoma WHO grade IV between 1990 and 2007 at our department. The association to patient survival was estimated using log-rank test for univariate analysis and cox regression method for multivariate analysis. RESULTS Median patient age was 62 years (mean: 60.4 years, range: 22-93 years), the male: female ratio was 1.26:1. Primary genesis was found in 91.0% of cases. A multifocal tumor was present in 110 cases (22.4%). The median pre- and post-operative Karnofsky Performance Score was 70. Total tumor resection was performed in 288 cases (58.5%), subtotal removal in 134 cases (27.2%). The following parameters were significantly associated with survival in univariate analysis: age, performance, primary genesis, multifocal tumor, neurological deficit, neuropsychological findings, seizures, incidental finding, total or subtotal resection, radiotherapy, chemotherapy, combined radio-/chemotherapy with temozolomide, re-craniotomy, second tumor in patient history. The following parameters were significantly associated with survival in multivariate analysis: age, performance, multifocal tumor, total or subtotal resection, radiotherapy, chemotherapy, combined radio-/chemotherapy with temozolomide. CONCLUSION In addition to patient age and performance, we identified multiple lesions and resection status as independent prognostic factors. Radiotherapy, chemotherapy and combined radio-/chemotherapy with temozolomide were significantly associated with prolonged survival.

Activation of the supplementary motor area (SMA) during voluntary pelvic floor muscle contractions—An fMRI study

To identify cortical and subcortical regions involved in voluntary pelvic floor muscle control, functional magnetic resonance imaging (fMRI) was performed at 1.5 T in thirty healthy subjects (15 women, 15 men). The participants performed rhythmical (1 Hz) pelvic floor muscle contractions, which imitated the repetitive interruption of voiding. Since previous reports concerning the representation of pelvic floor muscles in the cortex of the medial wall are inconsistent, a conservative statistical threshold (FWE-corrected P<0.05) was used to detect the most robust foci of activation, and cytoarchitectonic probability maps were used to correlate the results with structural anatomical information. We found a strong and consistent recruitment of the supplementary motor area (SMA), with foci of peak activity located in the posterior portion of the SMA, suggesting that this region is specifically involved in voluntary pelvic floor muscle control. Further significant activations were identified bilaterally in the frontal opercula, the right insular cortex and the right supramarginal gyrus. They may reflect the attentive processing and evaluation of visceral sensations. Weaker signals were detected in the primary motor cortex (M1) and the dorsal pontine tegmentum. There was no significant correlation between bladder volumes and brain activation induced by pelvic floor muscle contractions. We found no significant gender-related differences.

Brain perfusion territory imaging applying oblique-plane arterial spin labeling with a standard send/receive head coil.

A new method for the selective spin labeling of left‐ or right‐sided supplying arteries of the brain without the need for additional RF coils is demonstrated. A clinical 1.5 T scanner was used. The spatial selectivity of the labeling process is based on the limited coverage of the excitation field of a standard send/receive head coil together with an oblique positioning of the labeling plane. A computer simulation was used to optimize key labeling parameters under the condition of laminar flow. The validity of the computer model results was confirmed by MRI measurements with a flow model. For human studies, a double‐inversion continuous arterial spin labeling (CASL) sequence was modified to allow for arbitrary positioning of the labeling plane. The obtained perfusion‐weighted images showed a clear delineation of the perfusion territories of the selected arteries in the anterior circulation of the brain and good gray/white matter contrast. Magn Reson Med 52:1443–1447, 2004.

Superselective arterial spin labeling applied for flow territory mapping in various cerebrovascular diseases.

In three example patients suffering from internal carotid artery occlusion, intracranial steno‐occlusive disease, and symptomatic arteriovenous malformation (AVM), a new method named superselective pseudo‐continuous arterial spin labeling (pCASL) was used in addition to clinical routine measurements. The capabilities of this method are demonstrated to gain important information in diagnosis, risk analysis, and treatment monitoring that are neither accessible by digital subtraction angiography nor by existing selective arterial spin labeling methods and thus to propose future applications in clinical routine. In all cases superselective pCASL enabled the assessment of tissue viability and of territorial brain perfusion at different levels starting from major brain feeding vessels to collateral circulation at the level of the Circle of Willis to even distal branching arteries. This made it possible to estimate the contribution of an extracranial‐intracranial bypass to the brain perfusion; to depict individual arteries to important functional brain areas; to identify en‐passant feeding vessels of an AVM and to track possible changes in their perfusion territories after intervention. J. Magn. Reson. Imaging 2013;38:496–503.

De novo development of intraosseous cavernous hemangioma

Intraosseous cavernous hemangiomas are rare and not often multifocal. De novo development of a skull cavernous hemangioma has not been described previously. We present a 20-year-old man who was operated upon for a skull cavernoma in the right frontal area and developed a new lesion 3 years later in the right occipital region. The first lesion was removed completely and the postoperative course was uneventful. Histology showed an intraosseous cavernous hemangioma. MRI follow-up revealed a new lesion in the right occipital region. At the time of the first operation this lesion was not seen on CT or MRI scan. Surgical removal was performed and histology again showed a cavernous hemangioma. The patient seems to be unique and it is important to keep young patients with the diagnosis of cavernous hemangioma under close follow-up. This supports the experience from parenchymatous cavernous hemangiomas that this malformation may become a dynamic disease.

Nasopharyngeal Extension of a Craniopharyngioma in a 4 Year Old Girl

Summary. Nasopharyngeal extension of a craniopharyngioma is very rare and usually presents with headache, nasal obstruction and visual disturbances. We present a case of a 4 year old girl, who became symptomatic with visual deterioration. MRI showed a huge supra – and infrasellar cystic craniopharyngioma with extension into the sphenoid sinus. Primary treatment was a transnasal puncture of the cyst followed by a subfrontal approach with removal of the tumour preserving the chiasm and optic nerves. The visual acuity postoperatively improved while she needed hormone replacement due to panhypopituitarism. Follow-up 12 months after the operation showed no recurrence. This is the youngest patient of about 27 patients reported so far in the literature.

Assessment of quantitative corticospinal tract diffusion changes in patients affected by subcortical gliomas using common available navigation software

OBJECTIVE The aim of this study is to analyze the quantitative DTI parameters of the CST in patients suffering from subcortical gliomas affecting the CST using generally available navigation software. METHODS A retrospective study was conducted on 22 subjects with diagnosis of primary cerebral glioma and preoperative motor deficits. Exclusion criteria were: involvement of motor cortex, lesion involving both hemispheres, previous surgical treatment. All patients were studied using magnetic resonance imaging (MRI) with diffusion tensor imaging (DTI) sequences. Volume, fractional anisotropy (FA) and mean diffusivity value (MD) of the entire CSTs were estimated. Moreover, distance from midline, diameters, FA and MD were calculated on axial images at the point of minimal distance between tumor and CST. Statistical analysis was performed. RESULTS There was a statistically significant difference of CST volume between affected and non-affected hemispheres (p<0.01). Mean overall/local FA, overall/local MD and sagittal diameter of CST were also significantly different between the two sides (p<0.05). Correlation tests resulted positive between the shift of CST and overall/local MD. Moreover there is significance between CST volume of tumor hemisphere and preoperative duration of motor deficits (p<0.05). CONCLUSION The present study has demonstrated for the first time a significant difference of DTI based quantitative parameters of the CST between a tumor affected and a non-affected hemisphere in patients with a corresponding motor deficit. This preliminary data suggests a correlation between DTI based integrity of CST and its function.

Brain Shift Correction Based on a Boundary Element Biomechanical Model with Different Material Properties

Neuronavigation systems are usually subject to inaccuracy due to intraoperative changes like brain shift or tumor resection. In order to correct for these deformations a biomechanical model of the brain is proposed. Not only elastic tissues, but also fluids are modeled, since an important volume of the head contains cerebrospinal fluid, which does not behave like soft tissues. Unlike other approaches, we propose to solve the differential equations of the model by means of the boundary element method, which has the advantage of only considering the boundaries of the different biomechanically homogeneous regions. The size of the matrix to invert is therefore drastically reduced. Finally, our method is assessed with sequences of intraoperative MR images, showing better performances for the elastic/fluid model than for the purely elastic one.

Clinical Aspects of Gliomas

Summary Tumors of the central nervous system represent a therapeutic challenge. Although there is a multitude of histological subgroups, the main entities are of astrocytic and oligodendrocytic origin. The majority of these lesions have an infiltrative nature, which is, in conjunction with the vicinity of highly specialized eloquent areas, highly demanding on the surgical skills and technologies applied. This paper discusses the clinical presentation, new technology and treatment algorithms currently employed in the treatment of these tumors.

Das interhemisphärische Subduralhämatom

ZusammenfassungDas interhämisphärische Subduralhämatom (ISH) nimmt unter den Subduralhämatomen eine Sonderstellung hinsichtlich seiner Lokalisation und Symptomatologie ein. Das Falx-Syndrom, bestehend aus einer kontralateralen, beinbetonten Hemiparese und das symptomfreie Intervall zwischen Unfallzeitpunkt und dem Auftreten klinisch neurologischer Herdsymptome sind hierbei die Hauptmerkmale. Häufig geht einem ISH nur ein Bagatelltrauma voraus, oder es besteht eine Gerinnungsstörung. Die konservative Therapie ist bei geringer neurologischer Symptomatik und klinisch stabilem Verlauf die Therapie der Wahl. Patienten mit progredienter Bewußtseinsstörung und fokal neurologischen Ausfällen sollten umgehend neurochirurgisch versorgt werden. Die bisherige Literatur von 99 Fällen wird zusammengefaßt und um drei eigene Verlaufsbeschreibungen erweitert.SummaryThe interhemispheric subdural hematoma (ISH) is a special subdural hematoma with regard to both location and symptomatology. The most widely described clinical signs and symptoms associated with an ISH are a lucid interval and the falx syndrome. The latter is featured by a contralateral hemiparesis that is accentuated in the lower extremity but spares the face. Minor head trauma or a preexisting coagulation disorder are also often found. Nonsurgical treatment should be chosen in patients with little neurologic dysfunction and a stable clinical course. Patients with progressive neurologic deterioration and focal neurologic deficits should be operated on without delay. This article provides a review of 99 published cases of ISH and adds 3 cases to the existing literature.