[Treatment of grade 0 intracranial aneurysms: Retrospective study of 79 cases]. / Traitement des anévrismes intracrâniens grade 0 : étude rétrospective portant sur 79 patients.

AIM: Without precise international recommendations, despite the advances of the ISUAA study, the superiority of microsurgery or endovascular treatment for unruptured intracranial aneurysm (UIA) over the natural history of this disease has not been proved. In this context, the authors evaluate their experience with the aim of assessing the results and risks of the different therapeutics and comparing them with the natural risk of this disease. MATERIAL AND METHOD: From January 1993 to July 2000, 79 patients harboring 110 UIAs were treated. These patients were divided retrospectively into two groups. Group A included 45 operated patients. Group B included 37 patients treated with endovascular coiling. The therapeutic choice was not randomized and was approved by a multidisciplinary neurovascular staff. RESULTS: The two populations were homogeneous in terms of age and sex. In group A, 12 patients presented early complications (26.6 %), with one death. In group B, 15.6 % of the patients presented an ischemic complication. After 1 year of follow-up, morbidity was 11.4 % in group A and 4.8 % for group B. Angiography found a partial recanalization in 12.5 % of the operated patients and in 33 % of the patients treated with endovascular coiling. DISCUSSION: Many factors are involved in the therapeutic decision: UIA location and size and individual risks. Progress in both surgery and interventional neuroradiology has led to good results conforming with the data reported in the literature but does not demonstrate the superiority of one technique over another.

[Imaging of brain tumors in children]. / Imagerie des tumeurs cérébrales de l'enfant.

Few studies exist in the literature on pediatric brain tumors examined with advances MRI techniques. The aim of this review is to try to find out some specific tissular characteristics of the main cerebral tumors encountered in children, especially through diffusion imaging, perfusion imaging and proton magnetic resonance spectroscopy (MRS). However, hemispheric cerebral tumors are not as common as in the adult population.

Endovascular treatment of idiopathic intracranial hypertension: clinical and radiologic outcome of 10 consecutive patients.

OBJECTIVE: To explore the relation between venous disease and idiopathic intracranial hypertension. BACKGROUND: Optic nerve sheath fenestration and ventricular shunting are the classic methods when medical treatment has failed. Idiopathic intracranial hypertension is caused by venous sinus obstruction in an unknown percentage of cases. Recently, endoluminal venous sinus stenting was proposed as an alternative treatment. METHODS: Ten consecutive patients with refractory idiopathic intracranial hypertension underwent examination with direct retrograde cerebral venography and manometry to characterize the morphologic features and venous pressures in their cerebral venous sinus. All patients demonstrated morphologic obstruction of the venous lateral sinuses. The CSF pressure was measured in all patients. The CSF pressure on lumbar puncture ranged from 27 to 45 mm Hg with normal composition. All patients had headache, and visual acuity loss was noted in eight patients. Funduscopic examination demonstrated papilledema for all patients. All patients had stenting of the venous sinuses. Intrasinus pressures were recorded before and after the procedure and correlated with clinical outcome. RESULTS: Intrasinus pressures were invariably reduced by stenting. For headache, six patients were rendered asymptomatic, two were improved, and two were unchanged after venous sinus stenting for a mean (+/- SD) follow-up of 17 +/- 10.1 months (range 6 to 36 months). Papilledema disappeared in all patients. In all cases, CSF pressure was normalized at 3-month follow-up. In all patients, direct retrograde cerebral venography or multidetector row CT angiography was performed at 6-month follow-up and demonstrated the absence of stent thrombosis. CONCLUSION: The importance of venous sinus disease in the etiology of idiopathic intracranial hypertension is probably underestimated. Patients with idiopathic intracranial hypertension in whom a venous sinus stenosis is demonstrated by a noninvasive radiologic workup should be evaluated with direct retrograde cerebral venography and manometry. In patients with a lesion of the venous sinuses who experienced medical treatment failure, endovascular stent placement seems to be an interesting alternative to classic surgical approaches.

Embolization-driven occlusion of the abdominal aortic aneurysmal sac as the basis of prevention of endoleaks in a new swine model.

OBJECTIVES: To assess the effect of a new polymer in embolization of endoleaks using an animal model. METHODS: A modified aortic stent-graft was placed in 20 pigs. Embolization was performed at the time of graft insertion with non-cytotoxic n-butyl-2-cyanoacrylate-metacryloxysulpholane and lipiodol (0.2:0.8ratio, 2 ml). Angiography, scanning electron microscopy and immuno-histochemistry were obtained at day 0, 1 week and 3 months. RESULTS: In control animals both type I and II endoleaks were demonstrated. In treated animals, neither type-I nor type-II endoleaks were observed and a fibro-proliferative response was demonstrated within the aneurysm thrombus. CONCLUSIONS: Host vascular responses govern the fate of the excluded aneurysm. Embolization of the sac and feeding arteries with non-cytotoxic glue sealed all occlusions by stimulating a massive restenosis-like process.

Retrospective study of 77 patients harbouring lumbar synovial cysts: functional and neurological outcome.

BACKGROUND: Synovial cysts represent an uncommon and probably underestimated pathological entity of the degenerative lumbar spine. The authors report a retrospective analysis of the clinical presentation, radiological studies and operative findings in 77 patients surgically treated for symptomatic lumbar synovial cysts at their institution. MATERIALS AND METHOD: Between January 1992 and June 1998, a total of 77 patients presenting with symptomatic lumbar synovial cysts were operated on in the author's department. Operative procedure, complications, results and pathological findings were correlated with preoperative assessment. There were 41 men and 36 women with an average age of 63 years (range 44-90 years). RESULTS: On the basis of their symptom complex on presentation, two populations were identified: patients who presented with a single radicular pain (group I = 51 patients), and patients who presented with bilateral neurogenic claudication (group II = 26 patients). Neurological examination on presentation demonstrated motor deficit (12%), sensory loss (26%) and reflex changes (35%). Degenerative disc disease and facet joint osteoarthritis was a frequent finding in patients with pre-operative MRI. Facet joint orientation was >45 degrees in 76.6% of patients. Preoperative spondylolisthesis was found in 48% on radiological studies. All the patients were treated surgically with resection of the cyst. No fusion was performed as a first line procedure. However subsequent fusion was necessary in one patient who developed symptomatic spondylolisthesis. Mean follow-up period was of 45 months ranging from 18 to 105 months. Only one recurrence occurred during the follow-up period. An excellent or good functional outcome was seen in 97.4% of cases, and 89% of the patients with motor deficit recovered. CONCLUSIONS: Surgical resection of lumbar synovial cysts is an effective treatment associated with very low morbidity. Synovial cysts are associated with increased grade and frequency of facet joint asteoarthritis but not with increased grade or frequency of degenerative disc disease compared with patients without cysts. In the author's opinion, at the present time, there is no reliable criterion which allows the development of a symptomatic spinal instability to be predicted in patients with a preoperative spondylolisthesis and therefore fusion as a first line procedure is still debatable.

[Endoscopic treatment of a voluminous benign symptomatic cyst of the pineal region responsible for an obstructive hydrocephalus]. / Traitement endoscopique d'un volumineux kyste bénin symptomatique de la région pinéale responsable d'une hydrocéphalie obstructive.

Asymptomatic non neoplastic cysts of the pineal region are common incidental findings in adults. On the contrary, voluminous and symptomatic cysts of the pineal region are rare and their management are not well defined. We present the case of a 32-year-old woman suffering who suffered from mild intracranial hypertension, gait disturbance and vertigo for one year. The neuroradiological workup showed a voluminous cyst of the pineal region responsible for an obstructive hydrocephalus. An endoscopic etiological treatment was decided. The operation consisted in a marsupialization of the cyst in the third ventricle with a stereotactic guidance system. A frozen section of the cyst wall failed to show tumoral cells. Immediate postoperative course was uneventful. Intracranial hypertension symptoms resolved in 24 hours. Clinical examination and neuropsychological testing were normal at two years postoperatively. The two years follow-up cerebral MRI demonstrated a remnant cystic cavity without mass effect and the patency of the aqueduct of Sylvius. Endoscopic treatment of symptomatic pineal cysts constitutes an interesting therapeutic alternative in the management of this pathology.

Depressed skull fracture overlying the superior sagittal sinus causing benign intracranial hypertension. Description of two cases and review of the literature.

The purpose of this report is to describe successful surgical treatment of benign intracranial hypertension (BIH) in two patients presenting with depressed skull fractures over the superior sagittal sinus (SSS). The first case involved a 22-year-old patient who presented with depressed skull fracture overlying the posterior third of the SSS. Symptoms of BIH developed within 48 h. The second case involved a 33-year-old patient who presented with depressed skull fracture overlying the junction between the middle and posterior thirds of the SSS. Symptoms of BIH developed 1 month after. Although this patient presented with bilateral papilloedema, the less straightforward nature of his BIH symptoms prompted us to undertake further neuroradiological assessment by angiography with retrograde venous catheterization. A high-pressure gradient was found between venous flow upstream and downstream from the compressed zone. Both patients underwent surgical decompression in the lateral decubital position. Continuous monitoring of intracranial pressure was begun upon induction of general anaesthesia. High preoperative pressure declined immediately after elevation of the depressed zone. Bleeding was not a problem at any time during the procedure. Follow-up MRI and angio-MRI demonstrated total restoration of SSS patency. Benign intracranial hypertension is an uncommon complication of depressed skull fracture. Retrograde venous catheterization with pressure measurement can be a useful diagnostic adjunct. Surgical treatment is indicated in symptomatic patients. Based on the two cases reported, we now propose MRI venography in all patients presenting with symptoms of BIH and arteriography with retrograde venous catheterization when venous sinus stenosis exists.

[Stereotactic mapping for radiosurgical treatment of vestibular schwannomas]. / Imagerie stéréotaxique de repérage dans le traitement radiochirurgical des schwannomes vestibulaires.

RATIONALE: As an exclusively image-guided surgery method, radiosurgery requires special attention in the choice of imaging modalities and acquisition parameters must be set with extreme care. METHODS: Quality control for resolution and accuracy of computed tomography (CT) scanners must be performed. Magnetic resonance imaging (MRI) distortions should be limited through magnetic field homogeneity adjustment (shimming) and acquisition parameters optimization. These inaccuracies should then be quantified through systematic combination of MRI and CT in the radiosurgery planning system. MRI pulse sequences selection criteria are defined by their ability to delineate tumor contrast enhancement and to image cranial nerves and vessels relative arrangement in the cistern and canal. Topography of the petrous structures, such as cochlea, vestibulum and facial nerve canal should be visible. Exact definition of real extension of the lesion at the end of the canal may require specific technical solutions. These technical requirements must be balanced depending on the lesion Volume staging (Koos), the treatment history (microsurgery), the clinical condition (hearing quality), the pathological context (NF2) or the age of the patient. RESULTS: T1-weighted Volumetric MRI pulse sequences (3D-T1) show a contrast enhanced signal that is useful for both the pons interface delineation in Koos III cases, and the canal ending in Ohata A and B. On the other hand, 3D-T1 introduce inaccuracies from magnetic susceptibility distortions and partial Volume effects. High resolution CISS T2-weighted Volumetric pulse sequences (3D-T2) give superior stereotaxic definition attributable to their better resolution (half a millimeter) minimizing partial Volume effects and to their lower magnetic susceptibility minimizing distortions. 3D-T2 allows direct nerve visualization. Moreover, this pulse sequence with contrast injection, show improved distinction between the pons and the nerves due to signal differences within the schwannomas. Fat saturation pulse sequences are of interest in post-microsurgery conditions. CONCLUSIONS: Radiology phase quality is critical and its complexity requires a high commitment to obtain satisfactory clinical results. Solelt the 3D-T1 MRI modality seems to us not to comply to minimum security criteria.

[Craniopharyngioma in children: MRI study of 43 cases]. / Les crAniopharyngiomes de l'enfant.

BACKGROUND AND PURPOSE: Craniopharyngiomas are intra-cranial tumors, relatively frequent in children, expanding in the pituitary stalk axis, from the third ventricle to the sphenoid body. Plain films and CT scan generally show a calcified lesion, deforming the sella turcica. MRI improves tumor description and topographic and structural analysis of the lesion. The aim of this study is to analyze the MRI aspect of craniopharyngiomas in a pediatric population and to correlate findings with surgical data. METHODS: MR and CT studies of 43 pediatric cases of histology-proven craniopharyngiomas were reviewed retrospectively. Tumor emergence, extensions and signal on different sequences were recorded. We searched for radio-surgical correlations. RESULTS: Craniopharyngiomas can be classified into two groups: intra-sellar tumors and third ventricle floor tumors (infundibulum and tuber cinereum). Preferential routes of extension are observed in each group correlated with consistency (cystic and/or solid). Surgical data confirmed these results. CONCLUSIONS: MRI is crucial for the pre-therapeutic evaluation of craniopharyngiomas allowing not only a detailed description of the tumor but also guiding therapeutic decisions. This series demonstrated that craniopharyngiomas exhibit two different types of localization and behavior. Embryonic development of the tumor explains the topographical differences.

Abscess-like formation concomitant with pituitary adenoma in Cushing's disease: case report and pathological considerations.

Pituitary abscess is a rare condition and a histological misnomer since cultures of abscess material are often negative or non-pathogenic. We report the first case of pituitary abscess-like formation concomitant with pituitary adenoma and discuss the physiopathological mechanism. A 37-year-old woman presented classic symptoms of Cushing's disease. Endocrine studies indicated the presence of adenocorticotropin (ACTH)-producing pituitary adenoma. Preoperative magnetic resonance imaging revealed two separate tumours of the pituitary. During transsphenoidal surgery, a 14-mm adenoma was removed from the right side of the gland and a pus-filled cystic tumour was opened and drained on the left. Histological diagnosis was ACTH-producing pituitary adenoma and cyst material compatible with pituitary abscess. Association of separate adenoma and abscess of the pituitary gland has not been reported previously. We speculate that spontaneous adenoma infarction may provide a more comprehensible pathophysiological explanation than abscess formation.

Resection of a giant intracranial dural arteriovenous fistula with the use of low-flow deep hypothermic cardiopulmonary bypass after partial embolization: technical case report.

OBJECTIVE AND IMPORTANCE: To describe the surgical resection of a giant intracerebral arteriovenous fistula with involvement of dura mater and surrounding bone. Intraoperative bleeding was controlled by hypothermic circulatory arrest. CLINICAL PRESENTATION: This 46-year-old woman complained of persistent headache for 1 year; her diagnostic workup revealed the presence of an arteriovenous fistula in the dura mater of the left temporal region fed by the meningeal artery of the external and internal carotid arteries, with normal run-off into Labbé's and Trolard's veins. Magnetic resonance imaging depicted a Chiari I malformation that was most likely a result of insufficient cerebral venous drainage. INTERVENTION: In preparation for surgery, staged embolization of feeders from the left meningeal artery and the left occipital artery was performed under controlled hypotension. This procedure failed to achieve a significant reduction in flow because of the immediate recruitment of internal branches of the internal carotid artery and dural branches of the right external carotid artery. Surgical treatment was undertaken without further embolization. Because of involvement of surrounding bone and the high risk of uncontrollable bleeding, the procedure was carried out with the patient under deep hypothermic cardiopulmonary bypass. Forty-five minutes of low flow (1.5 L/min) at 18 degrees C allowed total resection of the involved dura mater and surrounding bone. Postoperative recovery was marked by left brain edema that disappeared within 10 days. Findings on follow-up angiography were normal, and the patient was discharged with no neurological deficit. CONCLUSION: Low-flow deep hypothermic cardiopulmonary bypass can be used to control intraoperative bleeding for surgical excision of a giant intracerebral dural arteriovenous fistula.

Schizencephaly: correlation between the lobar topography of the cleft(s) and absence of the septum pellucidum.

The bipolar defects observed in schizencephalies-clefts in the hemispheric mantle on the one hand, absent septum pellucidum on the other--without any anatomic or functional continuity suggest that there is some sort of common specific vulnerability of both structures. A study of the correlation between lobar location of the clefts and involvement of the septum pellucidum was undertaken, considering the hypothesis that the septum pellucidum is the portion of a "medial medullary velum" that corresponds to the frontal lobe, while the psalterium would correspond to the parieto-occipital lobe and the fimbria corresponds to the temporal lobe. This retrospective study of 16 cases of schizencephaly properly investigated by MR discloses a perfect correlation, all cases with absent septum pellucidum having clefts into the frontal lobe, all cases with present septum pellucidum having clefts in the parietal, temporal, and occipital lobes, and only the few instances (3 cases) of overlapping findings being characterized by clefts in the central area, where the distinction between posterior frontal and anterior parietal lobes is uncertain because of the cortical dysplasia related to the clefts. Partial defects of the septum also proved to correlate closely, topographically, with the location of the clefts. Therefore, the facts confirm a segmental organization of the mantle and septal defects, suggesting a developmental rather than a destructive mechanism, which could at least be related to a segmental pattern of selective vulnerability.

[Advances in the contributions of imaging to stereotaxic localization of cerebral arteriovenous malformations for radiosurgery ]. / Evolution des données d'imagerie dans le repérage stéréotaxique pour la radiochirurgie des malformations artério-veineuses cérébrales.

Historically, angiography was one of the first diagnostic methods to allow for visualization of neurovascular structures. It has been and still is very useful for precise evaluation of vascular pathology and is one of the main elements in treatment planning for radiosurgical targets. It is the only imaging method that gives insight into the angioarchitecture of a cerebral arteriovenous malformation, possibly reducing the target volume. Construction of frames (Leksell, Fisher) that are compatible with cross-sectional imaging methods, such as CT and MRI allowed there use for planning of stereotactical treatment for brain cerebral arteriovenous malformations. The advantages of these methods are given by the fact, that they are less invasive and that they allow visualization of neurovascular structures and surrounding cerebral structures. Further evolution of the cross-sectional imaging techniques allowed reconstruction of the image data in different planes and segmentation of structures such as vessels. Use of special algorithms allow visualization of the image data, i.e. surface rendering with 3D images of vascular structures. However, such images allow no detailed insight into the angioarchitecture of a cerebral arteriovenous malformation and give rather a view of the whole volume, i.e. a "tumor" aspect of the cerebral arteriovenous malformation. Similar images are currently also obtained with digital substraction angiography using rotational image acquisitions and image postprocessing allowing 3D reconstruction of angiographical image data. The different image evaluation methods are thus complementary all giving useful information for treatment planning. Therefore it would be useful to develop the possibility to integrate the information obtained by these modalities. Image fusion require identification of fiducial marks, what can be performed with application of external marks or by using internal anatomical marks. Recent developments allow now use of vascular structures as fidiucial marks to obtain image fusion. This paper reports on the evolution of stereotactical planning, performed on 541 patients over a period of eight years.

[Gamma-knife radiosurgery for brainstem arteriovenous malformations. Preliminary results]. / Traitement radiochirurgical gamma-knife des malformations artério-veineuses du tronc cérébral. Résultats préliminaires.

BACKGROUND AND PURPOSE: Microsurgical resection have the advantage to be immediately effective according to bleeding risk and is the reference treatment for cerebral arteriovenous malformations. For cerebral arteriovenous malformations located in the brainstem gamma-knife radiosurgery due to its low invasivity is classically a first line treatment. We reviewed the Marseilles experience to assess the efficacy and safety of gamma-knife radiosurgery for brain stem arteriovenous malformations. METHODS: We analyzed retrospectively data of 45 patients with an arteriovenous malformation located in the brain stem treated in Marseilles by gamma-knife radiosurgery by between 07/92 and 12/99. Mean age was 42 years, there were 5 children. Arteriovenous malformations were located in the pons or midbrain for the majority of the patients. Intraaxial lesion was found in 82% of patients. Hemorrhage prior to radiosurgery occurred in 75% of the patients. Gamma-knife procedure was the first treatment of the arteriovenous malformations for 29 patients (65%); previous surgery was performed in 34 patients (15%). Mean nidus volume was 550 mm(3) (32-14 196 mm(3)). Mean margin dose was of 23 Gy (range 15-30 Gy). Follow up was available for 25 patients (mean 18 months). RESULTS: One patient presented a transient worsening of his neurological status, and 2 patients developed a fixed deficit. Two patients underwent rebleeding at an interval of 12 to 36 months after the gamma-knife procedure. At last angiographic follow-up (13 patients), the obliteration rate was 82% of the arteriovenous malformations. A second procedure was proposed to a patient with only partial occlusion at 3 years. CONCLUSIONS: Gamma-knife radiosurgery can achieve good obliteration rate of brain stem arteriovenous malformations with low morbidity and may be a valuable first-choice therapy for such arteriovenous malformations. A larger population and longer follow up are mandatory in order to confirm these preliminary results.

A report of the clinical use of the detach-18 mechanical detachable platinum coil in 41 patients.

BACKGROUND AND PURPOSE: The purpose of this study was to determine the safety and reliability of the mechanical detachment system of a new platinum coil, Detach-18, when used as a vascular occlusive device for neurovascular disease. METHODS: Forty-one patients (nine male and 32 female patients; age range, 26-75 years; mean age, 54.4 years) underwent treatment at seven centers. Twenty-two patients had dural arteriovenous fistulae of the transverse sinus treated by a transvenous route. Fourteen patients underwent internal carotid artery occlusion in the treatment of aneurysms, meningioma, facial tumor, or carotid injury. One patient underwent occlusion of the basilar artery and one patient underwent occlusion of the vertebral artery for treatment of aneurysms. In two patients, coils were used as part of the treatment of their arteriovenous malformations. In all cases, the Detach-18 coils were delivered through a microcatheter with two distal markers. Two types of coils, a 0.015-inch-diameter "regular" coil and a 0.014-inch-diameter "soft" coil, were used. RESULTS: A total of 569 coils were used, 541 of which were detached. The number of coils in ranged from four to 53 (average number of coils, 14). The coils passed easily through the microcatheter. The detachment maneuver occurred within 10 to 25 s with 20 turns of the introducing wire. No premature coil detachment occurred. Complete occlusion of the vessel lumen was achieved in 35 cases. In three cases, 80% to 90% occlusion was achieved. In two cases, 70% to 80% occlusion was achieved. There were no device-related complications. CONCLUSION: The detachment system was safe, reliable, consistent, and fast. This is a useful system for coil embolization in neurovascular applications.

Postoperative intracranial thrombolysis and angioplasty.

SUMMARY: The case study involves a patient presenting middle cerebral artery thrombosis, related to a severe vasospasm following subarachnoid hemorrhage due to aneurysm rupture. The patient was treated initially by surgical clipping of the left middle cerebral artery aneurysm. After surgery, the neurological status of the patient was normal. Six days later, the patient presented right hemiplegia and aphasia that were related to the proximal left middle cerebral artery thrombosis. Despite recent open-skull surgery, in situ thrombolysis using urokinase and antip late let antibodies (abciximab) was performed. The thrombosed artery was reopened and a severe vasospasm was observed. The vasospasm was treated by transluminal angioplasty. No intracranial hemorrhage was noted after thrombolysis and angioplasty, whereas subcutaneous hemorrhage around the scalp incision was observed. The patient recovered from motor and language impairment. The only long-term symptom was a mild dysorthographia. Balance of risk/benefit is discussed for such aggressive thrombolytic therapy. In this particular case, effectiveness and uneventful use of abciximab was demonstrated despite very recent brain surgery that was considered a formal contra-indication for the use of such a powerful thrombolytic drug. Vessel thrombosis is an exceptional complication of cerebral vasospasm. In the early hours, intra-arterial thrombolysis may be considered, but recent intracranial surgery is usually an exclusion criterion to performing thrombolysis. We report the case of a patient who underwent thrombolysis and angioplasty in the postoperative period to treat this complication of vasospasm.

Early and delayed MR and PET changes after selective temporomesial radiosurgery in mesial temporal lobe epilepsy.

We report a patient with medically refractory mesial temporal lobe epilepsy treated by gamma knife radiosurgery. In lieu of a microsurgical procedure, an entorhinoamygdalohippocampectomy was performed with a gamma knife and low marginal doses (25 Gy). The clinical and imaging studies, including CT, MR imaging, 18F-fluorodeoxyglucose positron emission tomography (FDG-PET), and long-term follow-up MR examinations, are reported. The patient has been seizure-free since the day of treatment, with no clinical complications. MR studies accurately depicted the effect on the target structures and the transient secondary changes around them. FDG-PET scans showed decreased metabolism after gamma knife surgery throughout the anteromesial part of the epileptogenic temporal lobe. This metabolic decrease was reversible in the lateral temporal cortex. Our case suggests that gamma knife surgery is a promising tool for use as a minimally invasive approach to the treatment of epilepsy.

Pineal region tumors: the role of stereotactic radiosurgery.

Between July 1992 and August 1995, 11 patients with pineal region tumors (PRTs) were treated at our center. Ages ranged from 8 to 72 years (median 21). Diagnosis was confirmed by histological examination in 7 patients. The remaining cases had strong neuroradiological and marker evidence of the diagnosis, so that a stereotactic biopsy could be avoided. The pathological diagnoses were pinealocytoma (n = 1), tectal astrocytoma (n = 1), germinoma (n = 2), pinealoblastoma (n = 2), and meningioma (n = 3). The marginal dose of these tumors ranged from 12 to 18-20 Gy. Conventional external radiotherapy was never used in this series. With a median follow-up of 12.3 months (range 2-34), all tumors responded to treatment and disappeared or ceased growing. We observed no mortality or major morbidity. One patient (tectal astrocytoma) had a mild radiation-induced reaction, with headache and transient worsening of an abducent nerve palsy, which were controlled with steroids. In germinomas and pinealoblastomas, recovery of normal cerebrospinal fluid circulation was observed in less than 7 days, in parallel with major tumor shrinkage. In this study we confirm that radiosurgery can be an effective and safe alternative for the treatment of pinealocytomas and low-grade tectal gliomas. Moreover, we consider that the characteristics of the radiosurgery technique suggest the method should be evaluated for the treatment of malignant PRTs.

First selective amygdalohippocampal radiosurgery for 'mesial temporal lobe epilepsy'.

All the well-documented radiosurgery of epilepsy cases are secondary epilepsies with space-occupying lesions. These results have prompted the idea of testing radiosurgery as a new way of treating epilepsy without space-occupying lesions. We have treated 4 patients with 'mesial temporal lobe epilepsy'. The preoperative evaluation programme was one we usually perform for patients selected for microsurgery of epilepsy. We report the baselines of this treatment, the radiosurgical protocol details, and preliminary results for the first patient treated (follow-up 16 months). Since treatment, the patient has been seizure free, but it is too soon to draw long-term conclusions about the efficiency of the radiosurgery of epilepsy. Morphological (MRI) and functional (PET scan) changes are discussed in relation to our technical choices. Our amygdaloentorhinohippocampal target has been selectively injured.

Location of hand function in the sensorimotor cortex: MR and functional correlation.

PURPOSE: To determine the location of hand function in the sensorimotor cortex using MR and positron emission tomography imaging studies. METHODS: Anatomic and physiological methods were used for this study. Anatomic study was based on the MR analysis of 22 subjects. The length of the sensorimotor cortex was measured in the axial and sagittal planes. Physiologic study was based on the positron emission tomography studies of 4 subjects. Each of the studies was correlated with MR. RESULTS: We found that the superior genu of the central sulcus corresponds to hand function in the sensorimotor cortex. This level may prove useful for any clinical correlations or for surgery. CONCLUSIONS: From this study, the hand function area in the sensorimotor cortex is easily understood with its characteristic shape in axial MR scan. The comparison of MR and positron emission tomography data clearly show anatomic correlations. This may be applied to the functional mapping of the pathologic studies in the sensorimotor cortex regions.