http://repub.eur.nl/res/aut/16287/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/27781/ 2010-12-01T00:00:00Z BACKGROUND AND IMPORTANCE: We report the occurrence of a primary intracranial extraosseous Ewing sarcoma/peripheral primitive neuroectodermal tumor (EES/pPNET) in the cerebellopontine angle in a child. CLINICAL PRESENTATION: A 10-year-old girl presented with symptoms and signs of an infratentorial space-occupying lesion that was confirmed by magnetic resonance imaging and followed up by subtotal surgical resection. Tumor cells displayed membranous expression of CD99, and one of the typical translocations of EES/pPNET (chromosome 22) was demonstrated by cytogenetic analysis. CONCLUSION: The literature regarding the histopathological, molecular, radiological, prognostic, and therapeutic features of intracranial EES/pPNET is reviewed, emphasizing the distinction of this entity from the central PNET. Although exceptionally rare, intracranial EES/pPNET should be considered in the differential diagnosis of lesions in the cerebellopontine angle. http://repub.eur.nl/res/pub/27510/ 2010-11-01T00:00:00Z Background: Previously, we reported on our single centre results regarding the diagnostic yield of stereotactic needle biopsies of brain lesions. The yield then (1996-2006) was 89.4%. In the present study, we review and evaluate our experience with intraoperative frozen-section histopathologic diagnosis on-demand in order to improve the diagnostic yield. Methods: One hundred sixty-four consecutive frameless biopsy procedures in 160 patients (group 1, 2006-2010) were compared with the historic control group (group 2, n∈=∈164 frameless biopsy procedures). Diagnostic yield, as well as demographics, morbidity and mortality, was compared. Statistical analysis was performed by Student's t, Mann-Whitney U, Chi-square test and backward logistic regression when appropriate. Results: Demographics were comparable. In group 1, a non-diagnostic tissue specimen was obtained in 1.8%, compared to 11.0% in group 2 (p∈=∈0.001). Also, both the operating time and the number of biopsies needed were decreased significantly. Procedure-related mortality decreased from 3.7% to 0.6% (p∈=∈0.121). Multivariate analysis only proved operating time (odds ratio (OR), 1.012; 95% confidence interval (CI), 1.000-1.025; p∈=∈0.043), a right-sided lesion (OR, 3.183; 95% CI, 1.217-8.322; p∈=∈0.018) and on-demand intraoperative histology (OR, 0.175; 95% CI, 0.050-0.618; p∈=∈0.007) important factors predicting non-diagnostic biopsies. Conclusions: The importance of a reliable pathological diagnosis as obtained by biopsy must not be underestimated. We believe that when performing stereotactic biopsy for intracranial lesions, next to minimising morbidity, one should strive for as high a positive yield as possible. In the present single centre retrospective series, we have shown that using a standardised procedure and careful on-demand intraoperative frozen-section analysis can improve the diagnostic yield of stereotactic brain biopsy procedures as compared to a historical series. http://repub.eur.nl/res/pub/22570/ 2009-08-01T00:00:00Z In this prospective, observational, 2-armed study, we compared the plasma amino acid profiles of patients undergoing awake craniotomy to those undergoing craniotomy under general anesthesia. Both experimental groups were also compared with a healthy, age-matched and sex-matched reference group not undergoing surgery. It is our intention to investigate whether plasma amino acid levels provide information about physical and emotional stress, as well as pain during awake craniotomy versus craniotomy under general anesthesia. Both experimental groups received preoperative, perioperative, and postoperative dexamethasone. The plasma levels of 20 amino acids were determined preoperative, perioperative, and postoperatively in all groups and were correlated with subjective markers for pain, stress, and anxiety. In both craniotomy groups, preoperative levels of tryptophan and valine were significantly decreased whereas glutamate, alanine, and arginine were significantly increased relative to the reference group. Throughout time, tryptophan levels were significantly lower in the general anesthesia group versus the awake craniotomy group. The general anesthesia group had a significantly higher phenylalanine/tyrosine ratio, which may suggest higher oxidative stress, than the awake group throughout time. Between experimental groups, a significant increase in large neutral amino acids was found postoperatively in awake craniotomy patients, pain was also less and recovery was faster. A significant difference in mean hospitalization time was also found, with awake craniotomy patients leaving after 4.53+/-2.12 days and general anesthesia patients after 6.17+/-1.62 days; P=0.012. This study demonstrates that awake craniotomy is likely to be physically and emotionally less stressful than general anesthesia and that amino acid profiling holds promise for monitoring postoperative pain and recovery. http://repub.eur.nl/res/pub/14216/ 2008-11-01T00:00:00Z http://repub.eur.nl/res/pub/32275/ 2008-11-01T00:00:00Z http://repub.eur.nl/res/pub/28905/ 2008-01-01T00:00:00Z Background. Frameless stereotaxy or neuronavigation has evolved into a feasible technology to acquire intracaranial biopsies with good accuracy and little mortality. However, few studies have evaluated the diagnostic yield, morbidity, and mortality of this technique as compared to the established standard of frame-based stereotactic brain biopsy. We report our experience of a large number of procedures performed with one or other technique. Patients and methods. We retrospectively assessed 465 consecutive biopsies done over a ten-year time span; Data from 391 biopsies (227 frame-based and 164 frameless) were available for analysis. Patient demographics, peri-operative characteristics, and histological diagnosis were reviewed and then information was analysed to identify factors associated with the biopsy not yielding a diagnosis and of it being followed by death. Results. On average, nine tissue samples were taken with either stereotaxy technique. Overall, the biopsy led to a diagnosis on 89.4% of occasions. No differences were found between the two biopsy procedures. In a multiple regression analysis, it was found that left-sided lesions were less likely to result in a non-diagnostic tissue sample (p = 0.023), and cerebellar lesions showed a high risk of negative histology (p = 0.006). Postoperative complications were seen after 12.1% of biopsies, including 15 symptomatic haemorrhages (3.8%). There was not a difference between the rates of complication after either a frame-based or a frameless biopsy. Overall, peri-operative complications (p = 0.030) and deep-seated lesions (p = 0.060) increased the risk of biopsy-related death. Symptomatic haemorrhages resulting in death (1.5% of all biopsies) were more frequently seen after biopsy of a fronto-temporally located lesion (p = 0.007) and in patients with a histologically confirmed lymphoma (p = 0.039). Conclusions. The diagnostic yield, complication rates, and biopsy-related mortality did not differ between a frameless biopsy technique and the established frame-based technique. The site of the lesion and the occurrence of a peri-operative complication were associated with the likelihood of failure to achieve a diagnosis and with death after biopsy. We believe that using intraoperative frozen section or cytologic smear histology is essential during a stereotactic biopsy in order to increase the diagnostic yield and to limit the number of biopsy specimens that need to be taken. http://repub.eur.nl/res/pub/35140/ 2007-11-01T00:00:00Z Background: Magnetic resonance imaging (MRI) of the brain is increasingly used both in research and in clinical medicine, and scanner hardware and MRI sequences are continually being improved. These advances are likely to result in the detection of unexpected, asymptomatic brain abnormalities, such as brain tumors, aneurysms, and subclinical vascular pathologic changes. We conducted a study to determine the prevalence of such incidental brain findings in the general population. Methods: The subjects were 2000 persons (mean age, 63.3 years; range, 45.7 to 96.7) from the population-based Rotterdam Study in whom high-resolution, structural brain MRI (1.5 T) was performed according to a standardized protocol. Two trained reviewers recorded all brain abnormalities, including asymptomatic brain infarcts. The volume of white-matter lesions was quantified in milliliters with the use of automated post-processing techniques. Two experienced neuroradiologists reviewed all incidental findings. All diagnoses were based on MRI findings, and additional histologic confirmation was not obtained. Results: Asymptomatic brain infarcts were present in 145 persons (7.2%). Among findings other than infarcts, cerebral aneurysms (1.8%) and benign primary tumors (1.6%), mainly meningiomas, were the most frequent. The prevalence of asymptomatic brain infarcts and meningiomas increased with age, as did the volume of white-matter lesions, whereas aneurysms showed no age-related increase in prevalence. Conclusions: Incidental brain findings on MRI, including subclinical vascular pathologic changes, are common in the general population. The most frequent are brain infarcts, followed by cerebral aneurysms and benign primary tumors. Information on the natural course of these lesions is needed to inform clinical management. Copyright http://repub.eur.nl/res/pub/20946/ 2007-08-01T00:00:00Z BACKGROUND AND PURPOSE: Our goal was to improve the preoperative assessment of the cortico- spinal tract (CST) in patients with brain tumors. We investigated whether the integration of functional MR imaging (fMRI) data and diffusion tensor (DT) tractography can be used to evaluate the spatial relationship between the hand and foot fibers of the CST and tumor borders. MATERIALS AND METHODS: We imaged 10 subjects: 1 healthy volunteer and 9 patients. Imaging consisted of a 3D T1-weighted sequence, a gradient-echo echo-planar imaging (EPI) sequence for fMRI, and a diffusion-weighted EPI sequence for DT tractography. DT tractography was initiated from a seed region of interest in the white matter area subjacent to the maximal fMRI activity in the precentral cortex. The target region of interest was placed in the cerebral peduncle. RESULTS: In the healthy volunteer, we successfully tracked hand, foot, and lip fibers bilaterally by using fMRI-based DT tractography. In all patients, we could track the hand fibers of the CST bilaterally. In 4 patients who also performed foot tapping, we could clearly distinguish hand and foot fibers. We were able to depict the displacement of hand and foot fibers by tumor and the course of fibers through areas of altered signal intensity. CONCLUSION: Incorporating fMRI into DT tractography in the preoperative assessment of patients with brain tumors may provide additional information on the course of important white matter tracts and their relationship to the tumor. Only this approach allows a distinction between the CST compo- nents, while visualization of the CST is improved when fiber tracking is hampered by tumor (infiltration) or perifocal edema. http://repub.eur.nl/res/pub/35814/ 2007-04-01T00:00:00Z http://repub.eur.nl/res/pub/35625/ 2007-01-15T00:00:00Z Accurate targeting of diseased and healthy tissue has significantly been improved by MRI/CT-based navigation systems. Recently, intraoperative MRI navigation systems have proven to be powerful tools for the guidance of the neurosurgical operations. However, the widespread use of such systems is held back by the costs, the time consumption during operation, and the need for MR-compatible surgical devices. Raman spectroscopy is a nondestructive optical technique that enables real-time tissue identification and classification and has proved to be a powerful diagnostic tool in a large number of studies. In the present report, we have investigated the possibility of distinguishing different brain structures by using a single fiber-optic probe to collect Raman scattered light in the high-wavenumber region of the spectrum. For the Raman measurements, 7 pig brains were sliced in the coronal plain and Raman spectra were obtained of 11-19 anatomical structures. Adjacent brain structures could be distinguished based on their Raman spectra, reflecting the differences in their biochemical composition and illustrating the potential Raman spectroscopy holds as a guidance tool during neurosurgical procedures. http://repub.eur.nl/res/pub/17653/ 1998-05-20T00:00:00Z Despite development in surgical techniques, chemotherapy and radiotherapy, most malignancies of the central nervous system are still devastating tumors with a poor prognosis. For example, median survival of patients with malignant gliomas (astrocytoma, oligodendroglioma or mixed rype) is roughly 12 months and only 5 % of the patients survive more than 5 years after diagnosis. Fifty % of astrocytomas are ryped as glioblastoma multiforme, the most malignant form of glioma. Glioblastoma account for 15-23 % of all intracranial tumors and have a very poor median survival of 6 months with conventional therapy. Metastases account for 15-30 % of all intracranial neoplasm's and develop in 25 to 30 % of all cancer patients. The overall median survival time after surgery followed by radiation therapy in solitary metastatic lesions ranges from 9 to 23 months, depending on the rype of primary cancer. The prognosis in patients with multiple metastases, however, is much worse. Lepto-meningeal metastases from solid tumors are of increasing importance in neuro-oncology, because of the increasing frequency and the severe neurologic disabiliry it causes. About 0.8 to 8 % of patients with cancer develop leptomeningeal metastases and median survival in these patients after radio- and chemotherapy ranges from 7 to 24 weeks.