18FDG-PET bei intrakraniellen Meningeomen versus Grading, Proliferationsindex, Zelldichte und zytogenetische Analyse

62 intrakranielle Meningeome von 60 Patienten wurden präoperativ durch 18FDG-PET untersucht, um den Zusammenhang zwischen 18FDG-Aufnahme und biologischem Tumorverhalten zu überprüfen. Als Parameter der Tumoraggressivität dienten histopathologisches Grading, Zelldichte, Ki-67-Proliferationsindex und Nachweis chromosomaler Aberrationen. Wir fanden einen signifikant erhöhten 18FDG-Uptake bei Grad 2- und 3- im Vergleich zu Grad 1-Meningeomen, bei zellreichen gegenüber mäßig zellreichen Meningeomen, und bei Tumoren mit einem erhöhten Ki-67-Proliferationsindex (über 2%). Die beiden Meningeome, bei denen die ausgeprägtesten chromosomalen Aberrationen beobachtet wurden, wiesen den höchsten 18FDG-Uptake unter den zytogenetisch untersuchten Meningeomen auf. Hieraus folgern wir, daß die 18FDG-PET zur Abschätzung der biologischen Aggressivität von intrakraniellen Meningeomen geeignet ist.

Subdural-atrial and subdural-peritoneal shunting in infants with chronic subdural fluid collections

BACKGROUND

In symptomatic infants with chronic subdural fluid collections a variety of treatment strategies, such as observation, repeated subdural tapping, external or internal subdural drainage, and craniotomy have been advocated. Until now, the ideal management for this etiologically heterogenous group of children seems controversial.

METHODS

The authors present their treatment with subdural-peritoneal and subdural-atrial shunts and the follow-up in 8 infants (mean age, 7 months) with bifrontal subdural hygromas and hematomas caused by different etiologic conditions.

RESULTS

Initially, all children were symptomatic, and repeated subdural taps showed no clinical and neuroradiologic benefit. Shunting resulted in disappearance of all clinical signs in all infants, with complete removal of the chronic subdural fluid collections in 6 cases and remarkable improvement in 2 cases. In all infants the shunt system was removed after disappearance of signs and decrease of fluid collections. As the only complication the shunt system had to be removed in 1 case on the fourth postoperative day because of infection without any further disadvantages. In none of the cases was a recurrence of the fluid collections seen during the follow-up.

CONCLUSION

These results suggest that in infants with symptomatic chronic subdural fluid collections who fail to respond to repeated tapping, the early placement of an unilateral subdural-peritoneal shunt with a low pressure valve represents a safe, benign, and effective treatment option.

Angiographic long-term follow-up data for arteriovenous malformations previously proven to be obliterated after gamma knife radiosurgery

OBJECTIVE

To investigate whether angiograms obtained 2 years after radiosurgery, proving total arteriovenous malformation (AVM) occlusion, represent the final state of treated AVMs and adjacent normal vessels.

METHODS

Angiograms were obtained for 48 patients 5 to 24 years after gamma knife radiosurgery and 4 to 17 years after the AVMs had been proven to be totally occluded after the treatment; changes in normal vessels and signs of recanalization were recorded. Ten of the patients developed clinical symptoms attributable to the AVMs or the treatment after having been declared cured, whereas the other patients did not exhibit symptoms.

RESULTS

There was evidence of AVM nidi at the sites of previously occluded AVMs for two patients and of nidi adjacent to those sites for another two patients. Three of the four recurrent AVMs were associated with hemorrhaging. All patients who experienced hemorrhaging from previously occluded AVMs were < or = 14 years of age at the time of gamma knife radiosurgery. There were signs of segmental narrowing in normal vessels that had been irradiated with high doses (nine patients) or a low dose (one patient). The segmental narrowing decreased with time for four of these patients, was unchanged for four, and increased for two. These vascular changes did not produce clinical symptoms in any of the patients.

CONCLUSION

There is a small possibility that AVMs may reappear after having been totally occluded after radiosurgery, especially in pediatric patients. Segmental narrowing in normal arteries after radiosurgery is a benign condition that rarely progresses and does not produce clinical symptoms.

Radiosurgical lesions in the normal human brain 17 years after gamma knife capsulotomy

OBJECTIVE

To our knowledge, this is the first long-term follow-up study of high-dose single-session irradiation to the human brain and provides new data concerning late tissue reactions after irradiation to small target volumes. The long-term lesional brain changes in 14 patients subjected to bilateral gamma knife capsulotomy for otherwise intractable anxiety disorders were retrospectively analyzed by magnetic resonance imaging.

METHODS

The prototype gamma unit was used for the radiosurgical procedure, and the collimators provided rectangular cross-sectional fields with an anteroposterior diameter of 3 mm and a transverse diameter of 5 or 11 mm. Maximum target doses were 120 to 180 Gy. Magnetic resonance imaging was performed 15 to 18 years (mean, 17 yr) after treatment, and dose-volume histograms were calculated for the dose distributions.

RESULTS

One patient had been irradiated twice on one side. In all but one of the remaining 27 targets, lesions with a volume of less than 100 mm3 were revealed by magnetic resonance imaging. The volumes of the lesions were confined within the volume corresponding to a minimum dose of approximately 110 Gy, with one exception. In one of three targets receiving a maximum dose of 120 Gy, no lesion was detected. There were no late radiation effects such as cyst formations, telangiectasias, hemorrhagic infarctions, or neoplasms.

CONCLUSION

This investigation indicates that a minimum dose of 110 Gy, with the currently used 4-mm collimator, to the edge of the target volume is required to create a lesion. The results prove that gamma knife surgery can be used in functional neurosurgery for producing small permanent lesions in the normal human brain.

Obsessive compulsive disorder and the right hemisphere: topographic analysis of lesions after anterior capsulotomy performed with thermocoagulation

Considerable but uncontrolled evidence suggests that stereotactic capsulotomy by means of thermolesions may provide symptomatic relief for patients with otherwise therapy refractory "malignant" obsessive compulsive disorder (OCD). Unlike in other functional stereotactic interventions, target localization for capsulotomy is based upon anatomical definition only. Few systematic attempts have been made to correlate the site and size of the capsular lesions with postoperative clinical outcome. Between 1976 and 1989 bilateral thermo-capsulotomy (TC) was performed in 22 OCD patients. In 19 patients complete quantitative pre- and postoperative psychiatric rating of OCD symptoms and long-term postoperative MRI studies were available. Cohorts of patients fulfilling criteria for good or poor outcome were contrasted, cases with intermediate treatment effect being excluded. Median postoperative MRI follow-up was 8.4 years (2.4-20.3 y). 9/19 patients fulfilled criteria for good postoperative outcome. In these patients all lesion sites overlapped covering a small area within the right anterior limb of the internal capsule. Lesions within the group of patients with poor outcome (n = 5) were located elsewhere, mostly further anterior in the internal capsule. Differences of lesion overlap between the two outcome groups were significant for the right side (Fisher's Exact Test: p < 0.005). Common topographic features of lesion sites within the right internal capsule were identified in OCD patients responding favourably to capsulotomy.

[Germinoma of the pineal area. Long-term follow-up after stereotaxic biopsy]

The current study analyses the long-term clinical course of 12 patients with pineal germinomas. The histological diagnosis was established by stereotactic biopsy in all cases. In 11 of the 12 cases the diagnosis was correct. There was no operative mortality or morbidity. All patients were treated by external radiotherapy. The median follow-up period for the surviving patients is 5.9 years (range 4.5-8.8 years). After radiotherapy, CT and MRI follow-up examinations showed complete tumor remissions with no local tumor recurrences in all cases. Two patients died of other, unrelated, illnesses 1.4 and 5.8 years after diagnosis of the pineal germinoma. Since long-term survival and morbidity do not document any superiority of operative resection of germinomas, the minimally invasive approach with stereotactic biopsy and radiotherapy is strongly advocated. There is no longer any justification for irradiating pineal tumors to check the diagnosis now that stereotactic biopsy is available.

PET-study of intracranial meningiomas: correlation with histopathology, cellularity and proliferation rate

The glucose metabolism of 62 meningiomas was measured by fluorine -18-2-fluorodeoxyglucose (FDG) PET and correlated with proliferation rate (Ki-67 index) and tumor cellularity. The mean metabolic rate (MRGlu) for meningiomas was 0.26 +/- 0.13 mikromol/g/min (range 0.08-0.62 mikromol/g/min). The relative tumor FDG-uptake (Q-MRGlu) (tumor/contralateral cortex) of all meningiomas was calculated with 0.73 +/- 0.37 (0.24-1.79). Differences of Q-MRGlu were significant between the groups with high vs. low cellularity (p < 0.01), increased vs. normal proliferation rate (p < 0.025) and low (WHO grade I) vs. higher (WHO grades II, III) graded tumors. In recurrent meningiomas (14 tumors) the glucose metabolism was not increased. The data show that 18 FDG-PET is suitable to serve as non-invasive predictor of tumor growth characteristics in meningiomas.

Monosomy 1p is correlated with enhanced in vivo glucose metabolism in meningiomas

The 2-[18F]fluoro-2-deoxy-D-glucose (FDG) uptake of 25 human meningiomas was preoperatively evaluated in vivo by positron-emission tomography (PET). After surgery, meningioma biopsies were analyzed cytogenetically. Five meningiomas showed partial monosomy for chromosome 1p additional to other typical chromosome aberrations. This aberrant karyotype was correlated with increased FDG uptake. Three of five meningiomas with monosomy 1p were classified as grade II according to WHO, while only one of 20 tumors without monosomy 1p was classified as grade II. Thus, monosomy 1p and elevated FDG uptake in PET are to be regarded as cytogenetic and metabolic parameters for the aggressiveness of meningiomas.

Bilateral chronic electrostimulation of ventroposterolateral pallidum: a new therapeutic approach for alleviating all parkinsonian symptoms

The global improvement of all parkinsonian symptoms after stereotactic pallidotomy has been demonstrated by Leksell. Recently, Laitinen, re-evaluating this target in the neurosurgical treatment of Parkinson's disease, confirmed the real value of this approach, and emphasized the necessity of locating the lesion in the ventroposterolateral part of the pallidum internum. Because we know that high-frequency stimulation of the ventrolateral part of the thalamus has the same clinical effect on tremor as high-frequency coagulation, this technique has now been applied bilaterally in one session in three patients who have severe Parkinson's disease, with akinesia and levodopa-induced dyskinesias in the foreground. The very satisfactory clinical results, up to 12 months in the first case, confirm the observation of Laitinen, but with the difference that the approach discussed here is both nondestructive and reversible, and unwanted side effects are avoided.

[18FDG-PET in intracranial meningiomas versus grading, proliferation index, cellular density and cytogenetic analysis]

62 intracranial meningiomas in 60 patients were studied with 18FDG-PET prior to neurosurgery in order to evaluate the relationship between 18FDG uptake and biological aggressiveness of the tumors. Histopathological grading, cellular density, Ki-67 proliferation index and evidence of chromosomal aberrations were used to assess tumor aggressiveness. Significantly elevated 18FDG uptake was found in grade 2- and 3- compared to grade 1-meningiomas, in tumors of high cellularity compared with those of low cellularity, and in meningiomas with an elevated Ki-67 proliferation index (above 2%). The two meningiomas with the most pronounced chromosomal aberrations revealed the highest 18FDG uptake of all cytogenetically studied meningiomas. We conclude that 18FDG-PET is useful for estimating the biological aggressiveness of intracranial meningiomas.

Chronic electrical stimulation of the VL-VPL complex and of the pallidum in the treatment of movement disorders: personal experience since 1982

Since 1982, we have been able to control involuntary movements associated with deaf-ferentation by means of chronic electrical stimulation of the thalamic sensory nucleus through implanted programmable neuropacemakers. Since 1987, we have been using the same system with electrodes chronically implanted in the VL for treating selected cases of tremor due to Parkinson's disease, multiple sclerosis and in cases of essential tremor. In our series of 60 patients, suppression of tremor was achieved in almost all cases; however, due to dysarthria in 30% of the cases (cases after previous thalamotomy in the other side or with bilateral stimulation), the amplitude of stimulation was corrected and thus some tremor was still observed. The rigidity of parkinsonism was in all cases improved. One case of hemiballism was perfectly controlled with the same technique. Finally, 3 cases of Parkinson's disease with severe hypokinesia, speech and gait disturbances, and on-off phenomenon have been globally improved by a bilateral chronic stimulation of the pallidum.

Bilateral chronic subdural haematomas following traumatic cerebrospinal fluid leakage into the thoracic epidural space

This report describes a patient who developed bilateral chronic subdural haematomas after a stab injury to the thoracic meninges causing prolonged cerebrospinal fluid leakage into the epidural space. Diagnostic findings and therapeutic management are presented and possible pathogenic mechanisms are discussed. This case suggests that patients who have symptoms or signs of increased intracranial pressure after a penetrating spinal injury should be studied for subdural haematoma.

Effect of recombinant tissue plasminogen activator on clot lysis and ventricular dilatation in the treatment of severe intraventricular haemorrhage

Twelve patients with severe intraventricular haemorrhage (IVH) underwent intraventricular thrombolysis with recombinant tissue plasminogen activator (rtPA). External ventricular drainage was performed in all patients within 24 hours of haemorrhage. Fibrinolytic therapy was started within 24 hours from the onset of symptoms in ten cases, and in two further cases after 48 hours and 5 days, respectively. Two to 5 mg of rtPA were injected via the ventricular catheter into one or both lateral ventricles. The injection was repeated at intervals ranging from 6 to 24 hours until CT scans demonstrated a substantial reduction of intraventricular blood. The total rtPA doses per patient ranged from 3 to 31 mg. CT scans showed a marked reduction of intraventricular blood and normalization of ventricular size within 24 to 48 hours from the beginning of the fibrinolytic therapy. Rapid reduction of elevated intracranial pressure by continuous diversion of cerebrospinal fluid could be achieved in all patients, because the ventricular catheters never became obstructed by clotted blood during the fibrinolytic therapy. During the period of treatment, the level of consciousness, as classified according to the Glasgow Coma Scale, improved from a mean value of 7 to 12. One fatal case of meningitis most probably due to the ventriculostomy was the only complication related to the treatment. This method of treatment might improve the prognosis in patients in whom a large intraventricular haematoma volume, ventricular dilatation, and impaired cerebrospinal fluid circulation are major determinants for the outcome.

Increased melphalan activity in intracranial human medulloblastoma and glioma xenografts following buthionine sulfoximine-mediated glutathione depletion

In previous studies we demonstrated that administration of buthionine sulfoximine (BSO) to athymic BALB/c mice bearing intracranial human glioma xenografts resulted in highly selective depletion of glutathione in neoplastic tissue with minimal effects on contralateral normal brain tissue. In the present study we treated athymic BALB/c mice bearing intracranial human glioma (D-54 MG) or medulloblastoma (TE-671) xenografts with melphalan alone or BSO followed by melphalan. Administration of BSO depleted intracellular glutathione to 7.5% of the control level. BSO plus melphalan resulted in a significant increase in median survival over that produced by melphalan alone: 45.3% versus 26.4% in TE-671 and 69% versus 27.6% in D-54 MG. These studies justify further efforts to modulate chemotherapeutic and radiotherapeutic interventions of primary malignant brain tumors by depletion of glutathione.

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.

On the difficulties encountered when establishing the correct diagnosis of disturbances in the pupillary reflexes

It is always difficult to interpret abnormalities in pupillary reflexes when a patient who has suffered injuries to the upper part of the face is unconscious. Nevertheless, thorough examination of pupillary reflexes can provide vital information about possible damage to the central nervous system. Decisions about treatment of and prognosis for patients with multiple injuries can be made more accurately when the status of the nerves supplying the eye are taken into account. Anatomical and physiological relationships of pupillary reflexes and oculomotor reactions in a patient with multiple injuries are discussed.