fMRI and acoustic analyses reveal neural correlates of gestural complexity and articulatory effort within bilateral inferior frontal gyrus during speech production

In an event-related fMRI study of overt speech production, we investigated the relationship between gestural complexity and underlying brain activity within bilateral inferior frontal gyrus (IFG). We operationalized gestural complexity as the number of active articulatory tiers (glottal, oral, nasal) and the degree of fine-grained temporal coordination between tiers (low, high). Forty-three neurotypical participants produced three types of highly-frequent non-word CV-syllable sequences, which differ systematically in gestural complexity (simple: ['dadada], intermediate: ['tatata], complex: ['nanana]). Comparing blood oxygen level-dependent (BOLD) responses across complexity conditions revealed that syllables with greater gestural complexity elicited increased activation patterns. Moreover, when durational parameters were included as covariates in the analyses, significant effects of articulatory effort were found over and above the effects of complexity. The results suggest that these differences in BOLD-response reflect the differential contribution of articulatory mechanisms that are required to produce phonologically distinct speech sounds.

Evaluation of Phonatory Behavior and Voice Quality in Patients with Multiple Sclerosis Treated with Deep Brain Stimulation

OBJECTIVES

The effect of deep brain stimulation (DBS) on phonatory behavior and voice quality in eight patients with multiple sclerosis (MS) was examined instrumentally and perceptually. The acoustic signals of vowel productions obtained from patients (produced with and without stimulation) and from a group of 16 healthy control speakers were analyzed to prove statistically the changes of phonatory behavior and voice quality.

STUDY DESIGN

This is a randomized study.

METHODS

Firstly, a new parametrization was used to determine phonatory behavior. Secondly, a perceptual evaluation of voice quality of the same speech material was performed.

RESULTS

With stimulation, phonation has a greater tendency to be strained. The results of perceptual evaluation support this strained phonation behavior under stimulation, resulting in a smaller degree of breathiness ratings of all raters. Without stimulation, an impaired and partly disturbed adduction of the vocal folds can be shown. These findings are also supported in the perceptual experiment providing a higher degree of hoarseness ratings of all raters for these signals.

CONCLUSIONS

High-frequency electrical impulses to the thalamus in patients with MS influence the phonatory behavior of their vocal folds. The results suggest the need for long-term monitoring of phonatory behavior during DBS to initiate adequate treatments without delay.

Improvement of upper limb ataxia and intention tremor allowing cessation of thalamic electrostimulation after four years

A 34-year-old female patient suffering from multiple sclerosis was treated with thalamic electrostimulation for right dominant brachial ataxia and intention tremor. At the end of the fourth year, the energy of the battery of the impulse generator was depleted. However, the patient was able to use her hands without major impairment with the stimulator OFF, due to a stable reduction of the degree of ataxia and intention tremor. The opposite thalamus received an electrode that was never activated because of a permanent thalamotomy effect. Thus, it can be concluded that restoration of function by means of deep brain stimulation might have been beneficial towards achieving a reorganization and stabilization of subcortico-cortical and cerebellar circuitry, supporting the process of self-repair in this patient with a less aggressive course of multiple sclerosis. However, scientific proof has yet to be found. This exceptional observation emphasizes the need for longterm studies.

Effect of bilateral stimulation of the subthalamic nucleus on different speech subsystems in patients with Parkinson's disease

The effect of deep brain stimulation on the two speech-production subsystems, articulation and phonation, of nine Parkinsonian patients is examined. Production parameters (stop closure voicing; stop closure, VOT, vowel) in fast syllable-repetitions were defined and measured and quantitative, objective metrics of vocal fold function were obtained during vowel production. Speech material was recorded for patients (with and without stimulation) and for a reference group of healthy control speakers. With stimulation, precision of the glottal and supraglottal articulation as well as the phonatory function is reduced for some individuals, whereas for other individuals an improvement is observed. Importantly, the improvement or deterioration is determined not only on the basis of the direction of parameter change but also on the individuals' position relative to the healthy control data. This study also notes differences within an individual in the effects of stimulation on the two speech subsystems. These findings qualify the value of global statements about the effect of neurostimulatory operations on Parkinsonian patients. They also underline the importance of careful consideration of individual differences in the effect of deep brain stimulation on different speech subsystems.

Effect of Deep Brain Stimulation on Different Speech Subsystems in Patients with Multiple Sclerosis

The effect of deep brain stimulation on articulation and phonation subsystems in seven patients with multiple sclerosis (MS) was examined. Production parameters in fast syllable-repetitions were defined and measured, and the phonation quality during vowel productions was analyzed. Speech material was recorded for patients (with and without stimulation) and for a group of healthy control speakers. With stimulation, the precision of glottal and supraglottal articulatory gestures is reduced, whereas phonation has a greater tendency to be hyperfunctional in comparison with the healthy control data. Different effects on the two speech subsystems are induced by electrical stimulation of the thalamus in patients with MS.

Quantification of temporal and spatial accuracy of alternating arm movements in multiple sclerosis patients treated with deep brain stimulation of the thalamic ventralis intermedius nucleus (VIM)

OBJECTIVE

In patients with multiple sclerosis (MS) ataxia is a common symptom, which is barely influenced by pharmacological treatment. We studied whether stimulation of the thalamic ventralis intermedius nucleus (VIM) improves the performance of alternating forearm movements in MS patients.

METHODS

We investigated 6 patients with primary (n=1) or secondary (n=5) chronic progressive MS (age 36-66 years, median 41.5 years, median EDSS [expanded disability status scale] 6.5). Patients were seated in a chair with one arm abduced at right angles to the body. This arm was strapped into a splint with one fixed section for the upper arm and one movable section for the forearm. The latter allowed horizontal movements in the elbow joint. The patients had to perform rhythmic alternating flexion and extension movements in the elbow joint. The rhythm and spatial extent of movements were indicated acoustically by a click tone stimulator and by marks respectively. Six manoeuvres (spatial extents of 48 degrees , 83 degrees at frequencies of 0.9 Hz, 1.5 Hz, and 2.5 Hz each) had to be performed. A potentiometer converted the horizontal movements of the forearm into a variable voltage. Forearm movements were measured with and without contralateral VIM stimulation.

RESULTS

In all patients, spatial accuracy of the alternating forearm movements improved significantly after the stimulation had been switched on. Temporal accuracy increased during VIM stimulation in 5 of 6 patients. In 1 of 6 patients the spatial but not the temporal movement accuracy improved during stimulation.

CONCLUSIONS

During VIM stimulation, performance of alternating forearm movements improved significantly. This might indicate that VIM stimulation could be a therapeutic alternative in the treatment of upper limb ataxia in MS.

A randomized trial of deep-brain stimulation for Parkinson's disease

BACKGROUND

Neurostimulation of the subthalamic nucleus reduces levodopa-related motor complications in advanced Parkinson's disease. We compared this treatment plus medication with medical management.

METHODS

In this randomized-pairs trial, we enrolled 156 patients with advanced Parkinson's disease and severe motor symptoms. The primary end points were the changes from baseline to six months in the quality of life, as assessed by the Parkinson's Disease Questionnaire (PDQ-39), and the severity of symptoms without medication, according to the Unified Parkinson's Disease Rating Scale, part III (UPDRS-III).

RESULTS

Pairwise comparisons showed that neurostimulation, as compared with medication alone, caused greater improvements from baseline to six months in the PDQ-39 (50 of 78 pairs, P=0.02) and the UPDRS-III (55 of 78, P<0.001), with mean improvements of 9.5 and 19.6 points, respectively. Neurostimulation resulted in improvements of 24 to 38 percent in the PDQ-39 subscales for mobility, activities of daily living, emotional well-being, stigma, and bodily discomfort. Serious adverse events were more common with neurostimulation than with medication alone (13 percent vs. 4 percent, P<0.04) and included a fatal intracerebral hemorrhage. The overall frequency of adverse events was higher in the medication group (64 percent vs. 50 percent, P=0.08).

CONCLUSIONS

In this six-month study of patients under 75 years of age with severe motor complications of Parkinson's disease, neurostimulation of the subthalamic nucleus was more effective than medical management alone. (ClinicalTrials.gov number, NCT00196911 [ClinicalTrials.gov].).

Peroperative transcranial sonography for electrode placement into the targeted subthalamic nucleus of patients with Parkinson disease: technical note

BACKGROUND

In the search for a better preoperative knowledge of the position of probes and electrodes, we assessed the feasibility and the usefulness of transcranial sonography during surgery for the implantation of stimulation electrodes into the subthalamic nucleus (STN) of patients with Parkinson's disease.

METHODS

Transcranial sonography was carried out during stereotactic surgery in 8 patients with Parkinson's disease who had a suitable temporal bone window on the side receiving the electrode. Test stimulation parameters were 130 Hz, 0.1 ms, up to 0 to 4.5 V.

RESULTS

The test probe with a diameter of 0.8 mm was visualized through the temporal preauricular window. The correct anatomic position of the electrode tip could be indirectly assessed thanks to the topographic relationship of the STN with the hyperechogenic substantia nigra and the nucleus ruber. The tip position of the final electrode was easily documented. A laterality of 10.5 to 11.5 mm, verified by teleradiographic ventriculography and plain films, was correlated with the best response of symptoms of Parkinson's disease to electrical impulses delivered to the STN.

CONCLUSIONS

Transcranial sonography is easily feasible during stereotactic surgery. In combination with the clinical effects of electrostimulation on the symptoms of Parkinson's disease and with stereotactic x-ray images, it enables the assessment and the documentation of the correct position of implanted STN electrodes in real time.

Improvement of Apraxia of Lid Opening by STN-Stimulation in a 70-Year-Old Patient with Parkinson's Disease

We report on a 70-year-old female patient with Parkinson's disease, who showed an improvement of a preexisting apraxia of lid opening on electrical impulses, so-called deep brain stimulation (DBS) delivered to the subthalamic nucleus (STN). This was not described by any other authors before. Up to now, the appearance of apraxia of lid opening was observed only as a side effect after deep brain stimulation in the nucleus subthalamicus. We suggest that these differences may be due to the region of the nucleus subthalamicus that is influenced by the stimulation.

Bilateral high-frequency electrical impulses to the thalamus reduce voice tremor: acoustic and electroglottographic analysis. A case report

An 81-year-old female patient suffering from disabling Holmes' tremor affecting both upper extremities, the head and additionally the vocal apparatus underwent bilateral thalamic ventralis intermedius nucleus (v.i.m.) stimulation. With the stimulation ON, the patient experienced complete suppression of the limb and head tremor and thorough voice normalization. Acoustic and electroglottographic (EGG) analysis showed a tendency towards hyperfunctional phonation with the stimulation ON as well as OFF, but a less disturbed vocal cord vibration pattern with the stimulation ON in comparison with a group of normal female speakers. This example shows that long-term monitoring of the vocal apparatus under deep brain stimulation therapy (DBS) of movement disorders must be planned in order to modify the stimulation parameters, if necessary, or to initiate logopaedic treatment.

[Effect of deep brain stimulation on glottal phonation in patients with Parkinson's disease and multiple sclerosis]

The present study examines the effect of neurostimulatory operations on glottal phonation of 3 parkinsonian patients and 3 patients with multiple sclerosis. With the help of two voice analysis programs (MDVP from Kay Elemetrics and EEG Program by Marasek) for the acoustic and electroglottographic definition of voice characteristics, vowel productions of the patients, which were recorded under two conditions (with and without stimulation), were analysed. In a first step, significantly different intrasubject means in the two conditions indicate the effect of neurostimulation. The strength of the effect differs among subjects, particularly in the case of patients with Parkinson's disease. In a second step, a gender-differentiated comparison of the individual patient's data (recorded with and without stimulation) with a group of normal voice speakers (150 male and 150 female speakers) is carried out. This intersubject comparison proves useful in that it relativizes the results from the intrasubject comparison. It is shown for the parkinsonian patients that stimulation causes a relative deterioration of the glottal cycle, while for the patients with multiple sclerosis a tendency for hyperfunctional phonation is observed. In the latter case, the results suggest the need for long-term monitoring of phonation behaviour during chronic electrical stimulation.

Differential modulation of subcortical target and cortex during deep brain stimulation

The combination of electrical deep brain stimulation (DBS) with functional imaging offers a unique model for tracing brain circuitry and for testing the modulatory potential of electrical stimulation on a neuronal network in vivo. We therefore applied parametric positron emission tomography (PET) analyses that allow characterization of rCBF responses as linear and nonlinear functions of the experimentally modulated stimulus (variable stimulator setting). In patients with electrodes in the thalamic ventrointermediate nucleus (VIM) for the treatment of essential tremor (ET) here we show that variations in voltage and frequency of thalamic stimulation have differential effects in a thalamo-cortical circuitry. Increasing stimulation amplitude was associated with a linear raise in rCBF at the thalamic stimulation site, but with a nonlinear rCBF response in the primary sensorimotor cortex (M1/S1). The reverse pattern in rCBF changes was observed with increasing stimulation frequency. These results indicate close connectivity between the stimulated nucleus (VIM) and primary sensorimotor cortex. Likewise, stimulation parameter-specific modulation occurs at this simple interface between an electrical and a cerebral system and suggests that the scope of DBS extends beyond an ablation-like on-off effect: DBS could rather allow a gradual tuning of activity within a neuronal circuit.

Initial evaluation of the feasibility of single photon emission tomography with p-[123 I]iodo-L-phenylalanine for routine brain tumour imaging

p-[123I]iodo-L-phenylalanine (IPA) is a recently described radiopharmaceutical which is highly accumulated in gliomas. The present investigation was designed to evaluate the feasibility of single photon emission tomography (SPET) with IPA to image brain tumours under routine clinical conditions. Using a dual- and a triple-headed SPET camera, whole-body kinetic and brain SPET, as well as plasma, urinary and dosimetric analysis were determined in four patients with gliomas after intravenous injection of IPA. Results obtained by IPA SPET were retrospectively compared with histopathology, magnetic resonance imaging and positron emission tomography with [18F]fluorodeoxyglucose. Tumour lesions were clearly demonstrated by IPA SPET at 30 min, 1h and 4.5h post-injection, even in patients with low grade gliomas. In patients with glioblastoma, excellent visualization of the tumour was possible even at 7h p.i., indicative of the high retention of the radiopharmaceutical in cerebral gliomas. Analysis of the radioactivity in plasma and urine attested to the high in vivo stability of IPA. Blood clearance was rapid (> 65% after 10 min) and IPA was excreted predominantly by the kidneys, the urinary radioactivity excretion ranging from 27% at 1h to 54% of injected doses at 5h p.i. The average effective dose for adults was estimated to be 0.0152mSv*MBq(-1), leading to an effective dose of 3.8mSv in a typical brain SPET investigation with 250 MBq IPA. This result strongly suggests that IPA is a potentially valuable brain tumour imaging agent for widespread clinical studies with SPET. Its high specific tumour uptake and retention even in low grade gliomas represent a major advantage compared to presently available SPET radiopharmaceuticals. Moreover, the radiation dose estimates indicate that clinical use of IPA will result in acceptable radiation dose levels in humans.

Clinical value of iodine-123-alpha-methyl-L-tyrosine single-photon emission tomography in the differential diagnosis of recurrent brain tumor in patients pretreated for glioma at follow-up

PURPOSE

To assess the clinical potential of iodine-123-alpha-methyl-L-tyrosine (IMT) and single-photon emission tomography (SPET) in the differential diagnosis of recurrences in patients pretreated for gliomas at follow-up.

PATIENTS AND METHODS

Seventy-eight patients were examined after primary therapy over 36 months. Histopathologic diagnoses of all patients was known at first treatment; magnetic resonance and/or computed tomography examination was performed in addition to IMT-SPET. Cerebral SPET images were acquired 20 minutes after intravenous application of 190 +/- 10 MBq of IMT. SPET images were classified as positive or negative for recurrent tumor visually and by calculating the ratios between tracer accumulation in the lesion and the unaffected contralateral regions of reference using region of interest. Final diagnoses were based on prospective clinicopathologic findings obtained independently of IMT-SPET.

RESULTS

IMT-SPET detected all high-grade recurrent gliomas (grade 4; sensitivity, 100%). A difference could be demonstrated in grade 2 and 3 recurrences (sensitivity, 84% and 92%, respectively). Moreover, benign posttherapeutic lesions (postoperative scars, radiation necrosis) were correctly diagnosed as negative for tumor recurrence. In general, IMT uptake in grade 2 (1.45 +/- 0.24) was significantly lower than that in grades 3 (1.70 +/- 0.41) and 4 (1.88 +/- 0.32). However, it was difficult to evaluate tumor grade only from the IMT accumulation in individual cases.

CONCLUSION

IMT-SPET seems highly useful for detecting and delineating recurrent gliomas and differentiating between benign posttherapeutic lesions and malignant tumor tissue. It may be a valuable clinical tool to diagnose recurrences in patients pretreated for gliomas at follow-up. However, it showed limitations in determining histologic tumor grade.

Distribution of epidermal growth factor receptor protein correlates with gain in chromosome 7 revealed by comparative genomic hybridization after microdissection in glioblastoma multiforme

In a recent study, 23 microdissected areas of 10 glioblastoma multiforme (GBM) were investigated for quantitative genomic aberrations using comparative genomic hybridization (CGH). To validate the chromosomal aberrations, as revealed by CGH after microdissection, parallel tissue sections were stained immunohistochemically with an antibody that detects both wild-type epidermal growth factor receptor (EGFR) and the deletion mutant form of the receptor (EGFRvIII). Immunostaining was correlated with CGH data of chromosome 7, because chromosome 7 is the most frequently aberrant chromosome in GBM (here four of 10 tumors), and this aberration often indicates an abnormality of EGFR. Nine of nine areas that showed gain in or amplification (2 areas) of chromosome 7 with CGH contained EGFR-immunoreactive cells. Only three of 14 areas without abnormality of chromosome 7 in CGH contained EGFR-immunoreactive cells; eleven of 14 areas were immunonegative. Our findings demonstrate a strong correlation between immunohistochemistry of EGFR and the copy numbers of chromosome 7, as revealed by CGH after microdissection in glioblastoma multiforme.

Successful low-dose intracavitary irradiation of a Rathke's cleft cyst with colloidal rhenium-186

Symptomatic recurrence of an histologically verified intra- and suprasellar Rathke's cleft cyst (RCC) was observed 4 months following transsphenoidal microsurgery. The space-occupying cyst was treated by endocavitary irradiation with colloidal rhenium-186 via a previously implanted catheter with an attached subcutaneous reservoir. The calculated dose of 4.4 Gy was able to stop the production of cyst fluid. Follow-up after intracavitary irradiation extends over 13 months. The cyst, with an initial size of 3 x 3 x 4 cm, has been reduced to 1.1 x 1.06 x 1.2 cm. The production of cyst fluid has decreased from 25 - 30 ml within 2 months before treatment to zero. The patient's visual and mental status as well as her quality of life are normal.

Thalamic stimulation for essential tremor activates motor and deactivates vestibular cortex

BACKGROUND

The functional effects of deep brain stimulation in the nucleus ventralis intermedius (VIM) of the thalamus on brain circuitry are not well understood. The connectivity of the VIM has so far not been studied functionally. It was hypothesized that VIM stimulation would exert an effect primarily on VIM projection areas, namely motor and parietoinsular vestibular cortex.

METHODS

Six patients with essential tremor who had electrodes implanted in the VIM were studied with PET. Regional cerebral blood flow was measured during three experimental conditions: with 130 Hz (effective) and 50 Hz (ineffective) stimulation, and without stimulation.

RESULTS

Effective stimulation was associated with regional cerebral blood flow increases in motor cortex ipsilateral to the side of stimulation. Right retroinsular (parietoinsular vestibular) cortex showed regional cerebral blood flow decreases with stimulation.

CONCLUSIONS

Beneficial effects of VIM stimulation in essential tremor are associated with increased synaptic activity in motor cortex, possibly due to nonphysiologic activation of thalamofrontal projections or frequency-dependent neuroinhibition. Retroinsular regional cerebral blood flow decreases suggest an interaction of VIM stimulation on vestibular-thalamic-cortical projections that may explain dysequilibrium, a common and reversible stimulation-associated side effect.

[Neuropathological and neuroradiological aspects of acute disseminated encephalomyelitis (ADEM)]

Among non-neoplastic lesions of the central nervous system, demyelinating pseudotumors of the group of acute disseminated encephalomyelitis (ADEM) most frequently occasion neurosurgical intervention for purposes of definitive diagnosis and thus enter the domain of the surgical pathologist. Typically, ADEM presents with multifocal, bilateral lesions in an asymmetrical distribution. Especially monolocular manifestations may be diagnostically challenging. Due to the acuteness of clinical symptoms and the expansive, space-occupying character of the lesions a diffuse glioma, a metastatic disease, a primary cerebral Non-Hodgkin's lymphoma, brain abscess, a parasitosis or an ischemic brain tissue necrosis may be suspected. This impression is supported by uptake of contrast-medium most pronounced at the periphery of the lesion and the subcortical location. The histomorphologic feature of relative axonal preservation in areas with acute myelin breakdown and lymphocytic infiltrates make the diagnosis of an acute primary demyelinating disease probable. A diagnosis of glioma may be prompted by the florid, cytologically atypical astrogliosis especially in intraoperative request. Based on a series of 14 cases of radiologically and bioptically documented cases of ADEM typical examples will be demonstrated and discussed.

Expression of cancer testis genes in human brain tumors

Cancer-testis (CT) genes are expressed in a variety of human cancers but not in normal tissues, except for testis tissue, and represent promising targets for immunotherapeutic and gene therapeutic approaches. Because little is known about their composite expression in human brain tumors, we investigated the expression of seven CT genes (MAGE-3, NY-ESO-1, HOM-MEL-40/SSX-2, SSX-1, SSX-4,HOM-TES-14/SCP-1, and HOM-TES-85) in 88 human brain tumor specimens. Meningiomas expressed only HOM-TES-14/SCP-1 (18% of meningiomas were HOM-TES-14/SCP-1 positive) and did not express any other CT genes. One ependymoma was negative for all CT genes tested. SSX-4 was the only CT gene expressed in oligodendrogliomas (2 of 5 cases), and it was also expressed in oligoastrocytomas (3 of 4 cases) and astrocytomas (10 of 37 cases). Astrocytomas were most frequently positive for HOM-TES-14/SCP-1 (40%) and SSX-4 (27%), followed by HOM-TES-85 (13%), SSX-2 (11%), and MAGE-3 (7%). Whereas MAGE-3 was detected only in grade IV astrocytomas, the expression of the other CT genes showed no clear correlation with histological grade. Of 39 astrocytomas, 60% expressed at least one CT gene, 21% expressed two CT genes, and 8% coexpressed three CT genes of the seven CT genes investigated. We conclude that a majority of oligoastrocytomas and astrocytomas might be amenable to specific immunotherapeutic interventions. However, the identification of additional tu-mor-specific antigens with a frequent expression in gliomas is warranted to allow for the development of widely applicable polyvalent glioma vaccines.

Ultrasound-based navigation during intracranial burr hole procedures: experience in a series of 100 cases

BACKGROUND

To establish a rational basis for intraoperative ultrasound guidance in neurosurgical procedures via a single burr hole approach based on the experience of one hundred cases.

METHODS

The single burr hole approach is carried out using a bayonet-shaped ultrasound transducer with a tip dimension of 8 x 8 mm. The ultrasound probe with a mounted puncture adapter fits a standard burr hole and allows real-time imaging of the ongoing surgical steps.

RESULTS

One hundred cases with five indications have been operated on so far: tapping of the ventricular system (46 patients), tapping of intracranial cysts (23 patients), biopsy of intracranial tumors (15 patients), evacuation of intracranial abscesses (9 patients), and evacuation of intracerebral hematomas (7 patients). Depending on their size, the ventricles could be clearly visualized in 34 of 46 patients. In the remaining patients the free margin of the falx served as orientation. Two ventricles could neither be visualized nor entered. Visualization and puncture of intracranial cysts were easy to achieve throughout, as was the case with abscesses. Tumor biopsy was unsuccessful in two patients harboring lymphomas at distances of more than 50 mm from probe to target. Intracerebral hematomas were easily visualized but, due to the presence of clots, aspiration was impossible in two patients. One patient with a giant glioblastoma died the day after the uneventful biopsy due to increased cerebral edema. No other complications occurred.

CONCLUSIONS

The presented method of ultrasound-based neuronavigation is an easy-to-use, fast, and safe technique of real-time imaging for free-hand single burr hole procedures.

Evidence of focal genetic microheterogeneity in glioblastoma multiforme by area-specific CGH on microdissected tumor cells

The term "multiforme" in glioblastoma multiforme (GBM) indicates the highly variable histomorphology that cannot be addressed by studies on homogenized tissue probes. In order to relate genetic findings with histomorphologically distinct areas we used microdissection to procure defined cell populations from microscopic tissue sections under direct visualization. Formalin-fixed and paraffin-embedded tissue sections of 10 GBM were evaluated for intratumoral genetic heterogeneity by microdissection of multiple areas of 20-50 tumor cells and DOP-PCR of DNA isolated from the dissected cell groups, followed by comparative genomic hybridization (CGH). Microdissected cells from histomorphologically normal extratumoral blood vessels from the same slides served as controls. The individual tumors showed variable combinations of primary chromosomal gains and losses common to all studied areas of a given case along with secondary, area-specific additional aberrations. CGH displayed a wider variety of chromosomal aberrations than metaphase cytogenetics of cell cultures from the same tumors. The most frequent aberrations observed were previously unperceived gains on chromosomes 4q (8/10) and 5q (5/10). Other nonrandom aberrations were gains on 12q (6/10), 13q (6/10), and 7 (5/10), and losses of 22 (5/10). Amplifications on 7p were intratumorally heterogeneous and only found in single areas of 2 tumors. In contrast to normal extratumoral vessels, vascular proliferates in most cases demonstrated chromosomal aberrations (CGH) which were partially different from the aberrations observed in the tumor itself. The described method gives evidence of considerable intratumoral genetic heterogeneity in GBM and provides a sensitive tool for the detection of quantitative chromosomal changes that are present only regionally within a given tumor.

Genetic heterogeneity in human astrocytomas: spatial distribution of P16 and TP53 deletions in biopsies

Smear preparations of 23 fresh astrocytoma biopsies were analyzed by two-color fluorescence in situ hybridization with cosmids specific for the P16 and the TP53 genes. Additionally, tissue sections of the same tumors were immunostained with the use of a monoclonal antibody that recognizes both wild-type and mutant TP53 protein. In 21 astrocytomas, loss of P16 was observed in a significant proportion of cells. Cells with homozygous P16 loss were present in 13 astrocytomas; 14 astrocytomas showed cells with heterozygous loss of P16. Remarkably, 5 astrocytomas showed a scattered mosaic pattern of cells with homozygous and, respectively, heterozygous p16 loss. Homozygous deletion of TP53 was not observed. Cells with heterozygous TP53 loss were detected in 12 tumors, in 7 of them in association with P16 loss. One tumor showed aberrant cells for neither TP53 nor P16 but strong immunostaining for TP53. Positive TP53 immunostaining was found in 16 astrocytomas. Heterozygous loss of TP53 was significantly correlated with TP53 protein expression. We conclude that, unlike typical tumor suppressor genes, P16 might enhance cellular proliferation after heterozygous loss through a dosage effect and that the distribution of cells with homozygous loss of P16 speaks in favor of a polyclonal loss of the second copy of this gene.

A positron emission tomographic study of subthalamic nucleus stimulation in Parkinson disease: enhanced movement-related activity of motor-association cortex and decreased motor cortex resting activity

BACKGROUND

Long-term high-frequency stimulation of the subthalamic nucleus (STN) improves akinesia in Parkinson disease. The neural correlates of STN stimulation are not well understood. Positron emission tomography can be applied to the in vivo study of the mechanisms of deep brain stimulation.

OBJECTIVE

To study changes in regional cerebral blood flow as an index of synaptic activity in patients with Parkinson disease with effective STN stimulation on and off during rest and movement.

METHODS

Eight patients with Parkinson disease who had electrodes implanted in the STN underwent 12 measurements of regional cerebral blood flow with water O 15 positron emission tomography at rest and during performance of paced freely selected joystick movements, both with and without STN stimulation (3 scans per experimental condition). Motor performance and reaction and movement times were monitored. Statistical parametric mapping was used to compare changes in regional cerebral blood flow between conditions and differences in activation.

RESULTS

All patients showed improvement in reaction and movement times during scans with the stimulator on. As predicted, increases in activation of rostral supplementary motor area and premotor cortex ipsilateral to stimulation were observed when stimulation was on during contralateral movement (P<.001). Unpredicted observations included decreases in regional cerebral blood flow in primary motor cortex at rest induced by STN stimulation.

CONCLUSION

Stimulation of the STN reduces the movement-related impairment of frontal motor association areas and the inappropriate motor cortex resting activity in Parkinson disease.

Evaluation of l-3-[123I]iodo-alpha-methyltyrosine SPET and [18F]fluorodeoxyglucose PET in the detection and grading of recurrences in patients pretreated for gliomas at follow-up: a comparative study with stereotactic biopsy

Based on the results of stereotactic biopsy, we evaluated in a prospective fashion the efficiency of l-3-[123I]iodo-alpha-methyltyrosine-single-photon emission tomography (SPET) and [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET) in the detection and grading of recurrences in patients previously treated for gliomas. The patient population comprised 30 individuals, nine with astrocytomas of grade II, ten with astrocytomas of grade IV, three with oligoastrocytomas of grade II, six with oligodendrogliomas of grade II and two with anaplastic oligodendrogliomas of grade III) suspected of recurrence and scheduled for further treatment. IMT SPET data were acquired using either by dual-or a triple-headed SPET camera, Multispect 2/3. FDG uptake was measured with an ECAT ART PET camera. Two independent observers classified PET and SPET images as positive or negative for tumour tissue. Uptake of FDG and IMT was evaluated visually and, in the case of IMT, also quantitatively by calculating the ratios between tracer accumulation in the lesion and the unaffected contralateral regions of reference using the region of interest (ROI) technique. The PET and SPET results were compared with the histopathological findings obtained either by stereotactic biopsy or in one case by open surgery. Glucose metabolism and amino acid uptake of recurrences of brain tumours as assessed by FDG-PET and IMT-SPET correlated highly with the histopathological findings. Based on the histopathological data, FDG-PET and IMT-SPET findings confirmed recurrence in all cases of high-grade gliomas (IV). A difference could be demonstrated in low-grade (II-III) tumour recurrences. True-positive IMT-SPET results were found in 86% of grade III and 75% of grade II recurrences, whereas FDG-PET yielded a sensitivity of 71% in tumours of grade III and 50% in those of grade II. With respect to the grade of malignancy of brain tumours at recurrence, IMT-SPET, in contrast to FDG-PET, does not permit adequate in vivo grading of non-mixed brain tumours of astrocytic or oligodendroglial origin. However, in this study FDG-PET did not permit discrimination between upgrading of low-grade oligoastrocytomas (II) into anaplastic oligodendrogliomas (III) and upgrading into glioblastomas (IV) The results of this study indicate that FDG-PET and IMT-SPET are equivalent to stereotactic biopsy in their ability to identify high-grade tumours at recurrence. IMT-SPET proved to be superior to FDG-PET in confirming low-grade recurrences. In the case of suspected progression of the grade of malignancy in ordinary gliomas, FDG-PET correlated significantly with the histopathological grading, whereas IMT-SPET did not. However, tumour grading by FDG-PET has a limitation in mixed brain tumours in that it is not possible to discriminate between progression of the oligo- versus the astrocytic tumour entity. In this case histopathological evaluation of the tumour grade remains necessary.

[Contribution of nuclear medicine to the diagnosis of recurrent brain tumors and cerebral radionecrosis]

The evaluation of brain tumor recurrence and therapy-induced benign changes following surgery and/or irradiation is a diagnostic challenge for imaging methods based on either morphology (cCT/MRI) or function (SPECT/PET). Current literature and the present data of our own patients demonstrate the diagnostic efficiency of IMT-SPECT and FDG-PET in the detection of recurrence and in-vivo grading. Thirty-nine patients suspected of brain tumor recurrence at follow-up were studied by FDG-PET and IMT-SPECT. Thirty-four of 39 patients showed recurrences; in 12 cases even a change in the grade of malignancy was observed. All high-grade recurrences could be confirmed by either methods. IMT-SPECT showed a higher sensitivity in detecting low-grade tumors at recurrence. In contrast to IMT-SPECT, FDG-PET supports sufficient in-vivo grading. Both methods can be used to differentiate between tumor recurrence and radionecrosis. In conclusion the results of our study demonstrate the efficiency of IMT-SPECT and FDG-PET in confirming recurrences and determining the actual tumor grade.

Long-term effect of electrostimulation of the subthalamic nucleus in bradykinetic-rigid Parkinson's disease

The motor effects of unilateral stimulation of the subthalamic nucleus on hypokinesia were studied in two patients 58 and 52 years old, both modified Hoehn and Yahr 2.5, at 16 and 15 months after the implantation of a quadripolar electrode (Medtronic). Motor UPDRS, time in the pegboard test, walking time, tapping, and serial reaction times were recorded. Chronic unilateral stimulation was associated with reversible improvement of measures of reaction time and hypokinesia > 1 year after the stereotactic electrode implantation. The beneficial effect was mainly contralateral to the stimulation. However, improvement of axial functions was also observed (phonation, walking).

Stereotactic neurosurgery planning with 3-D spiral CT-angiography

OBJECTIVE

To assess the feasibility and value of spiral CT angiography of the brain vessels for the planning of neurosurgical stereotactic interventions.

MATERIAL AND METHODS

Fourty-two patients harboring cerebral lesions underwent spiral CT angiography prior to stereotactic biopsy. Thin spiral CT slices with a collimator slice thickness of 1 mm and a pitch of 1 were used. Multiplanar reconstructions and maximum intensity projections (MIP) were obtained as well as 3-D tissue definition.

RESULTS

There was a sufficient visualization of vessels and of their relationship to the lesion. Tumor neovascularization was clearly demonstrated. Arteries could be shown separately. Stereotactic coordinates of targets were chosen at a safe distance from the vessels and the simulation of tarjectories using the cine loop was made possible. In three cases the presence of a pathological vascularization warned against a stereotactic biopsy.

CONCLUSION

Spiral CT angiography seems to yield enough topographical information for the accurate planning of stereotactic surgery for brain lesions. CT angiography with the helical technique is rapid and less invasive than digital subtraction angiography.

Short-term CT and MR changes in brain tumors following 125I interstitial irradiation

PURPOSE

The study was undertaken to assess characteristic short-term CT and MR changes in brain tumors following 125I interstitial irradiation.

METHOD

Sixteen patients were included who had both CT and MR control examinations at regular intervals over a period of 18 months following treatment. Two groups were distinguished: low grade tumors (11 cases) and high grade malignancies (5 patients). 125I seeds were used as temporary implants. The cumulative dose was 50-60 Gy.

RESULTS

In some patients of both groups, a low attenuation spheric structure with a contrast-medium-enhanced ring and a diameter of 6-8 mm was observed. There was no edema around the structure, which represents a zone of tissue necrosis at the site of the temporary 125I implant. Tumors in both groups were completely destroyed, some decreased in size, and others were unchanged. Pseudotumor necrosis with accompanying edema occurred in two patients with low grade astrocytoma, the diameter of which was > 4 cm.

CONCLUSION

The behavior of cerebral tumors and their appearance on CT and MR images after interstitial irradiation seem to be variable. Decrease in tumor size may take place at different intervals after therapy. Brachytherapy of tumors with a diameter of > 4 cm may produce space-occupying radionecrosis.

[Rare intracranial plasmacytoma manifestations. Case reports and review of the literature in diffuse plasmocytoma, in primary solitary extramedullary plasmacytoma in in primary solitary osseous plasmacytoma]

Plasmacytomas can be divided into multiple, solitary osseous and solitary extraosseous/extramedullary plasmacytomas. Intracranial plasmacytomas of the dura, leptomeninx and cerebrum are well known from the literature. They are manifestations of multiple myeloma, intracranial extramedullary plasmacytoma or metastatic disease of extramedullary plasmacytoma in distant locations. We describe a cerebellar manifestation of a solitary plasmacytoma of the bone, and a leptomeningeal carcinomatosis of a multiple plasmacytoma. A summary of the literature concerning intracranial plasmacytomas is given. Dural manifestations of plasmacytoma have the same features as meningiomas in CT or MRI. Cerebral or cerebellar manifestations cannot be differentiated from brain tumors by means of CT or MRI. In CT, plasmacytomas show high-density lesions. T2w-MRI reveals a low-intensity lesion. In T1w-MRI, intense homogeneous contrast enhancement can be demonstrated.

[CT-angiography in planning stereotaxic biopsies]

Twenty-one patients referred for stereotactic biopsy were studied by CT angiography. Helical CT with 1 mm collimation was obtained (pitch of 1:1). Multiplanar reconstructions were performed; maximum intensity projections and shaded-surface displays were generated by connectivity-based editing tools. The visualization of cerebral vessels was excellent. No further conventional angiography was needed. Improved information was obtained about localization of the intracranial lesion and its relationship to neighboring vessels. No bleeding complications were detected by CT after stereotactic biopsy.

Early proliferation enhancement by monosomy 10 and intratumor heterogeneity in malignant human gliomas as revealed by smear preparations from biopsies

We performed simultaneous fluorescence in situ hybridization (FISH) with centromere-specific DNA probes for chromosomes 7 and 10 and Ki-67 proliferation labelling on smear preparations of 17 differentiated and anaplastic human astrocytomas and glioblastomas. In 15 of the 17 cases studied, Ki-67-positive clones differed from Ki-67-negative clones mainly by the loss of one copy of chromosome 10, either combined with or independent of trisomy 7. The findings suggest that monosomy 10 is an earlier event than generally supposed in the development of human gliomas and that it is directly related to cellular hyper-proliferation.

[Correlation of preoperative neuroradiologic with postoperative histologic diagnosis in pathological intracranial processes]

PURPOSE

To determine the accuracy of preoperative neuroradiological diagnosis of pathological intracranial processes in a prospective study.

MATERIALS AND METHODS

A team of three neuroradiologists determined the diagnosis in CT, MR and angiography prior to stereotactic biopsy or operative resection (173 patients). Only one diagnosis was allowed, except in those cases with two equally probable diagnosis (24 patients). In 106 patients a resection of a brain tumor, in 67 cases a stereotactic biopsy was performed. According to the histological diagnosis the patients were subdivided into three groups: 1: complete agreement: the single diagnosis was correct. 2: conditional agreement: on of the 2 differential diagnosis was correct. 3: no agreement

RESULTS

In 131 cases (76%) a complete agreement, in 24 cases (14%) a conditional agreement and in 18 patients (10%) no agreement were found. Assuming only stereotactic procedures the neuroradiological diagnosis was correct in 44 cases (66%) and incorrect in 10 cases (15%). In 13 patients (19%) one of the two differential diagnosis was correct. The specificity of the major tumors was calculated between 92% and 100%. The sensitivity for pituitary adenomas (n = 9) and neurinomas (n = 11) was 100%, the sensitivity for meningiomas (n = 32) was 94%. A sensitivity was calculated between 50% and 71% for astrocytomas (WHO I to WHO IV, n = 64) and metastases (n = 24).

CONCLUSION

The accuracy was found to be higher than in the comparable retrospective studies.

Polysyndactyly and asymptomatic hypothalamic hamartoma in mother and son: a variant of Pallister-Hall syndrome

We report on a 53-year-old woman and her 20-year-old son who both presented with polysndactyly, without other external malformations or mental retardation. MRI imaging revealed, as an incidental finding, asymptomatic hypothalamic hamartomas in both patients. The siblings of both mother and son are unaffected. This family may represent an autosomal dominant variant of Pallister-Hall syndrome.

Microsurgery of cerebral lesions under stereotactic conditions

Microsurgical excision of cerebral lesions was carried out under CT-guided stereotactic conditions. For lesions located in critical cortical areas, cerebral teleangiography under stereotactic conditions provided the coordinates of the vascular elements related to the structures and adjacent to the lesion without X-ray distortion. Small size cortical and subcortical lesions were targeted using the stereotactic biopsy probe as a guide. In twenty-four patients stereotactic microsurgery was used for following lesions: 8 cavernomas, 8 metastases, 7 gliomas, and 1 tuberculoma. Unpredictable permanent neurological complications did not occur, but predicted transient impairment after surgery in functional territories was tolerated with the complete removal of the lesion. The advantages of microsurgery using stereotactic coordinates are: precise knowledge of the location of brain structures and exact targeting of intracerebral lesions, better evaluation of surgical risks, easy spatial orientation, and minimization of the surgical damage to the healthy brain tissue.

Real-time ultrasound imaging of cerebral lesions during "target point" stereotactic procedures through a burr hole. Technical note

Stereotactic burr-hole procedures like biopsies of brain tumours based on CT scan or MRI and angiographic data have so far usually been carried out without real-time ultrasound image control. Intra-operative real-time ultrasound imaging was carried out during twelve target-point stereotactic procedures via a single standard burr-hole using a new slender ultrasound transducer with a diameter of 8 mm. The technical parameters of the transducer are: frequency range of 5 < - > 3.5 MHZ, phased array sector scan, 90 degree sector. The transducer has a bayonet-like configuration and can be sterilized. Sufficient quality of the images was achieved in these twelve cases with different pathological entities such as malformation cysts (3 cases), gliomas (7 cases), one metastasis and one intracerebellar haemorrhage. Moreover, co-ordinate values may be calculated from the ultrasound images generated peroperatively, allowing the surgeon to choose additional targets. Colour flow mapping provides the visualization of vascular structures. For the beginner stereotaxy may be easier to learn using ultrasound real-time imaging.

[Familial association of hypothalamic hamartoma and polysyndactyly]

Hypothalamic hamartomas are congenital malformations. The association between hypothalamic hamartomas and other dysplasias, including polydactyly, is known to be a neonatal lethal syndrome. We report on two patients (mother and son) with asymptomatic large hypothalamic hamartomas and polysyndactyly. The relationship of the patients suggests an autosomal dominant transmission.

Detection of numerical chromosome aberrations in brain tumours by fluorescence in situ hybridization on smear preparations of small tumour biopsies

We present a technique for the preparation and interphase cytogenetic analysis of native tumour cell nuclei from smear preparations of small biopsies of human brain tumours. The presence of tumour-specific numerical chromosome aberrations can be determined by fluorescence in situ hybridization (FISH) analysis using chromosome-specific repetitive DNA probes. The FISH analysis of smear preparations provides cytogenetic information about brain tumour samples, within 2 days, avoiding time-consuming and artefact-prone tumour cell culture.

Detection and quantification of vascular endothelial growth factor/vascular permeability factor in brain tumor tissue and cyst fluid: the key to angiogenesis?

In primary malignant brain tumors increased vascularity and marked edema strongly suggest a possible role of the vascular endothelial growth factor/vascular permeability factor (VEGF/VPF). This was confirmed by earlier in situ hybridization studies, by analysis of the expression of the mitogen in different subsets of glioblastoma cells, and by the fact that the VEGF/VPF receptor flt-1 (fms-like tyrosine kinase) is up-regulated in tumor cells in vivo. To assess and quantify the expression of the VEGF/VPF gene and of the receptor gene, 26 surgical specimens of brain tumor tissue from 24 patients were analyzed. In most malignant gliomas, the expression level of the VEGF/VPF gene is elevated and can be increased up to 20- to 50-fold in comparison with low-grade tumors. Using polymerase chain reaction-based amplification, it could be shown that the messenger RNAs of three different VEGF/VPF forms are synthesized in tumor tissue samples. Northern blot studies revealed that in some samples a significant expression of the gene coding for placenta growth factor, a growth factor closely related to VEGF/VPF, was observed. In addition, using a radioreceptor assay it was possible to detect high VEGF/VPF-like activity in the cyst fluids of brain tumors, indicating the accumulation of the mitogen and permeability factor in brain tumor cysts. Further investigations revealed that astrocytoma and glioblastoma cells in culture express the VEGF/VPF gene and secrete the VEGF/VPF protein, whereas gene expression of the two known VEGF/VPF receptors, kinase insert domain-containing receptor and flt-1, could not be detected. These data support previous reports, which stated that VEGF/VPF acts as a paracrine growth and permeability factor in brain tumors and may contribute to tumor growth by initiating tumor angiogenesis.

Acidic fibroblast growth factor (aFGF) is present in the fluid of brain tumour pseudocysts

Fluid samples from brain tumour pseudocysts were examined for the presence of Fibroblast Growth Factor (FGF). Fluids were collected from 6 patients with differentiated low grade gliomas (group A), 3 anaplastic gliomas (group B) and 3 metastases (group C). For FGF assays pooled fluids from group A, B, and C were subjected to affinity chromatography on a Heparin-Sepharose column. Each pool contained endothelial cell mitogenic activity which eluted in the 1.2 M NaCl fraction and to a lesser degree in the 0.6 M fraction of Heparin-Sepharose high affinity chromatography. Mitogenic activity in the 1.2 M NaCl fraction of Heparin-Sepharose chromatography suggests the presence of acidic FGF (aFGF).

Experimental radiofrequency (RF) coagulation with computer-based on line monitoring of temperature and power

The safety and reliability of radiofrequency coagulative techniques are questioned after each coagulation, especially in functional neurosurgery. In spite of the high level of technical development of modern surgical RF generators there is still uncertainty about the character of the coagulative lesion. For the present study, a 500 kHz RF generator was connected through a module for analog/digital conversion and for regulation to a personal computer provided with a software programme for the graphic display in real time of the RF power and of the temperature/time curves. The effects of thermocoagulation were studied in fresh egg white, and monopolar lesions were made in the subcortical white matter of rabbits with a probe with a 0.5 mm diameter and a bare tip of 3 mm in length. The regularity of thermocoagulation depends on the accurate temperature reading at the tip of the electrode. The ideal course of the temperature is a smoothly ascending curve from the level of 37 degrees C to the level present for coagulation, followed by a straight horizontal line. With too slow a response of the probe to temperature changes there is an inherent danger of overheating in the initial phase of the procedure. Additionally the power level has to be adjusted for each probe. On line monitoring with graphic display of the physical parameters provides a direct control of the course of the coagulation. Regular curves of the physical parameters without temperature overshoot correspond to reproducible lesions in vitro and in vivo.

Cerebral angiography under stereotactic conditions. Technical note

A simple system for cerebral angiography under stereotactic conditions using standard components is described. X-ray tubes and power generator belong to the usual equipment of the stereotactic operating room. A film changer and an injection pump were integrated into the stereotactic arrangement. Angiographic documents with reduced X-ray magnification were obtained. For topographical orientation 5 films per seriogram were sufficient. The system also allows stereoscopic viewing by performing an additional oblique sequence after the head ring is rotated exactly 6 degrees. The combination of the necessary diagnostic procedures, as CT scan, angiography, ventriculography, serial biopsy within a single three coordinate reference system offers considerable advantages for brain tumour patients.

Occlusion of experimental artery aneurysms by intrasaccular injection of fibrin sealant

Aneurysms were produced by grafting a vein pouch onto the cervical carotid artery of rabbits following the removal of an elliptical piece of the arterial wall. The diameter of the opening was 3-4 mm and the maximum height 8 mm. Through direct puncture of the aneurysm a clot of the fibrin sealant Tissucol was injected into the aneurysm. The sequential morphological changes were studied by light microscopy. One case was examined after 3 weeks by scanning electron microscopy. Complete resorption of the fibrin sealant was observed. The aneurysm cavity was filled with a dense connective tissue covered by a layer of newly formed endothelial cells.

Experimental aneurysms in the rabbit: occlusion by intrasaccular injection of fibrin sealant

Experimental aneurysms of the carotid artery were produced using the microsurgical technique of grafting a venous sack onto the artery in the neck of rabbits after the removal of an elliptical piece of arterial wall. Twenty-five aneurysms were occluded with the fibrin sealant Tissucol. Microscopic examination showed complete resorption of the fibrin clot and the formation of dense granulation tissue within the aneurysm, which was covered with a layer of endothelial cells after 2 weeks. The results are only tentative and require further experimental studies.

[Stereotaxic diagnosis of brain tumors in childhood as a principle for therapy planning]

Brain tumors of the various histologic types and topographical localization may occur in children. The incidence of brain tumors under the age of 15 years is 2.4-6.5/100,000. Due to the profound physiopathological differences between the various types of cerebral tumors can the choice of the adequate method of treatment not accurately be made without the exact knowledge of the histologic nature. Modern imaging techniques facilitate the visualization of cerebral lesions, do not furnish however a histologic diagnosis. Stereotactic biopsy allows by a direct approach to the lesion--without removal or retraction of healthy brain tissue, as well in the supra--as in the infratentorial space, to establish the histologic diagnosis. This is, together with the topographical localization and the volume, an essential factor for the choice between open surgery, external irradiation (teletherapy), stereotactic interstitial radiation therapy (brachytherapy), stereotactic endocavitary treatment or conservative management.

[Spatial definition of cerebral tumors]

The spatial definition of brain tumors can be obtained by CT and angiography carried out under stereotactic conditions. A standard CT software is used to obtain stereotactic coordinates of any intracranial point. Serial stereotactic biopsies provide a precise and detailed histologic diagnosis, including grading and volume estimation. The stereotactic approach is directed at a better understanding of the relationship between the brain and the lesion. It provides a rational basis for the choice among treatment modalities. Our experience so far with a series of 401 cases is reported on.

Cavum vergae cyst as a cause of hydrocephalus, "almost forgotten"? Successful stereotactic treatment

Cavum vergae cysts (CVC) are cerebral midline malformations, which usually have no clinical manifestations. In rare cases, however, non-communicating cysts can cause hydrocephalus by obstruction of the aqueduct. Initially, from 1930 to 1960 operative treatment consisted in open cysto-ventriculostomy, i.e. establishing a communication between CVC and the ventricles, via a transventricular approach. In the era of CT, symptomatic treatment of the hydrocephalus by ventriculo-atrial or ventriculo-peritoneal shunts is preferred. All the wellknown complications of shunting are encountered. Based on the experience of our cases of CVC with clinical manifestations, we here propose a definitive causal treatment which can be achieved by draining the cyst contents into the ventricles via a stereotactically introduced catheter.

Colloid cysts of the third ventricle. Open operative approach or stereotactic aspiration?

Colloid cysts of the third ventricle can cause hydrocephalus if they grow to the point where they occlude the foramina interventricularia. The operative approach via a craniotomy used to be the common method of treating these lesions. Now, in the era of CT- and MR-scanning, stereotactic aspiration should be preferred as an ideal method of simultaneously diagnosing and treating colloid cysts. Unlike open surgery, aspiration of colloid masses poses hardly any risk for the patient. Ten cases successfully treated by this technique are presented.

[Current significance of stereotactic exploration in the diagnosis and therapy of space-occupying cerebral processes]

To reach good functional results in patients with spaceoccupying processes--especially with those localized in the dominant hemisphere operative treatment should be planned individually, which is impossible if all diagnostic assessments are followed by the same surgical procedure. The choice of appropriate method of therapy in case of brain tumor depends on various factors, such as the histological nature, extent and volume, relationship to the brain structures and vessels, and spatial form of the growth. The synthesis of all neuroradiological information from stereotactic exploration, together with the histological findings from stereotactic serial biopsies yields a three-dimensional representation of the brain with the tumor. This method seems to offer the optimal basis for the choice of appropriate treatment--especially for gliomas--between surgery, radiotherapy (external or/and interstitial), endocavitary radiation therapy or drainage.