Biomedical subjects

O Levrier

Publications and source records attributed to O Levrier.

At least 19 recordsLinked to original sources

PubMed2005

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.

Adult↗

PubMed2005

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.

Animals↗

PubMed2005

[Endovascular treatment of benign intracranial hypertension by stent placement in the transverse sinus. Therapeutic and pathophysiological considerations illustrated by a case report].

We report a case of benign intracranial hypertension in a 31-year-old man treated by endovascular stent placement in the right transverse sinus. The patient presented with a typical benign intracranial hypertension syndrome. Ophthalmologic findings showed bilateral papilledema with a 7/10 loss visual acuity loss in the right eye and 2/10 in the left eye. At lumbar puncture, cerebrospinal fluid (CSF) pressure was 40 mmHg. Magnetic resonance imaging (MRI) showed slit ventricles and dilatation of optic nerve sheaths. optiques. After failure of medical treatment, the patient was referred to our neurosurgical department for therapeutic decision. Direct retrograde cerebral venography showed predominant cerebral venous drainage via the right transverse sinus which exhibited stenosis in its proximal third. Mamometry revealed a 25 mmHg pressure gradient across the point of stenosis. Due to possible venogenic benign intracranial hypertension, endovascular stent placement was proposed and accepted by the patient. At 3 months follow-up, the patient was symptoms free, papilledema had disappeared and visual acuity was 10/10 on both eyes. CSF pressure on lumbar puncture was 11 mmHg. The pathophysiological aspects and therapeutic management of this pathology illustrated by this are discussed along with a careful and exhaustive review of the literature.

Adult↗

PubMed2005

[Endoscopic treatment of a voluminous benign symptomatic cyst of the pineal region responsible for an obstructive hydrocephalus].

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.

Adult↗

PubMed2005

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.

Adult↗

PubMed2004

[Stereotactic mapping for radiosurgical treatment of vestibular schwannomas].

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.

Diffusion Magnetic Resonance Imaging↗

PubMed2003

Normal galenic drainage of the deep cerebral venous system in two cases of vein of Galen aneurysmal malformation.

INTRODUCTION: Vein of Galen aneurysmal malformations (VGAM) are assumed to be related to the persistence of the embryonic median prosencephalic vein of Markowski, which does not involute in cases of VGAM and becomes the venous collector of the shunt, characteristic of the malformation. The arterial feeders of VGAMs are all primitive meningeal arteries present during the embryonic period of the constitution of the malformation. It has also been assumed that the internal cerebral veins were absent in patients presenting with VGAM. There is no clear evidence indicating, however, that the deep venous structures cannot develop normally. CASE REPORTS: We report on two cases of VGAM in which superselective retrograde transvenous catheterization and MRI demonstrated that normal internal cerebral veins were draining into the aneurysmal vein of Galen. CONCLUSIONS: It is conceivable that, as in our patients, this drainage pattern is only angiographically detectable via selective retrograde transvenous drainage. The possibility of such normal deep galenic venous drainage must be considered in VGAM management, as it may imply occurrence of adverse effects when the malformation is occluded on the venous side.

Adult↗

PubMed2003

Efficacy and low vascular toxicity of embolization with radical versus anionic polymerization of n-butyl-2-cyanoacrylate (NBCA). An experimental study in the swine.

BACKGROUND AND PURPOSE: To compare the efficacy and vascular toxicity of embolization with radical (NBCA+metacryloxysulpholane=CS) versus conventional anionic (NBCA alone=CA) polymerization of NBCA. MATERIALS AND METHODS: Under continuous digital subtracted angiography (DSA) recordings, a 0.2 mL volume of identical glue mixtures were injected in a single-step procedure, concomitantly, in left and right (with CS and CA, respectively) renal arterial branches (RAB) and ascending pharyngeal arteries (APA) in 8 swines. Arterial histopathology and morphometry of inflammation were investigated at 2 weeks. RESULTS: Complete embolization was achieved with equivalent cast homogeneity on DSA with both NBCA mixtures in RAB and APA. Inflammatory crowns in APA and RAB were significantly lower in CS - than in CA-treated sites (p<0.001). CS plug was scarcely adhesive to the vascular wall, and pulled apart from the wall by a residual thrombotic lining; in contrast with CA casts that were strongly adhesive to walls with endothelium stripping. CONCLUSIONS: Anionic and radical polymerization of NBCA embolization was identical with regards to occlusion rate; whereas radical pathway of polymerization with cyanoacrylates lowered histotoxicity with a less sustained adhesiveness of casts against vascular walls.

Angiography, Digital Subtraction↗

PubMed2002

Performance of long J-shaped coils in large and giant intracranial aneurysms: an in vitro study.

We evaluated the performance of long straight coils (Detach-18 J-shaped coils) in large and giant in-vitro aneurysms. The coils consisted of a distal semicircular part 7 or 15 mm in diameter and a proximal 70 cm straight part having three types of stiffness: soft, standard, and stiff. We first investigated the ease of passage through a microcatheter in a realistic cerebral vessel model. Second, we made silicone models simulating lateral-type aneurysms of various spherical dome diameters (12, 15, 20 and 30 mm) and neck sizes (3-10 mm; dome-to-neck ratio approximately 3:1) and connected them to a pulsating circulatory pump. We evaluated the anchoring and folding patterns of the coils, stability of the microcatheter and coils in the aneurysm, and smoothness of delivery and retrieval of coils. Third, we compared the conformability of a coil in a large, irregular aneurysm with that of a spiral coil. The long J-shaped coils were easily advanced and retrieved through a microcatheter in a tortuous vessel model. In 12 mm spherical aneurysms, each coil made a complex framework, and knot formation or damage to the coil during withdrawal was often observed. In 15 mm aneurysms, the coils were all easily delivered and retrieved; standard-stiffness coils adapted best to this size. In 20 mm aneurysms, frameworks were less complex but still good with a standard or stiff coil, but those with soft coil were unstable and changed significantly within 3 min of detachment due to gravity and pulsatile flow. In 30 mm aneurysms, soft coils filled only the lower part during introduction, whereas a stiff coil still made a favourable framework. Conformability of a long J-shaped coil was superior to that of a spiral coil in a large, irregular aneurysm. Long J-shaped coils conform well to various configurations of large and giant aneurysms and can shorten procedures since a larger implant volume can be delivered with a single coil. Their principle of action may promote more favourable occlusion of irregular and large aneurysms by improved conformability and stability.

Embolization, Therapeutic↗

PubMed2002

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.

Abscess↗

PubMed2002

[Craniopharyngioma in children: MRI study of 43 cases].

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.

Adolescent↗

PubMed2001

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.

Arteriovenous Fistula↗

PubMed2001

Mechanical detachable platinum coil: report of the European phase II clinical trial in 60 patients.

PURPOSE: To determine the safety and reliability of the mechanical detachment system of a platinum coil (Detach-18) when used for neurovascular embolization. MATERIALS AND METHODS: Sixty patients (21 men, 39 women; age range, 26-75 years; mean age, 56.2 years) were treated in seven centers. Ease of introduction of the coil to the microcatheter, effect of coil passage on the microcatheter shape and stability during its delivery, retrievability of the coil before and after the transition zone passed beyond the microcatheter, detachment of the coil, and effect of coil rotation on the microcatheter stability were evaluated. The detachment system itself was evaluated for premature detachment, failure of the coil to detach, detachment time, number of turns, visibility of radiopaque markers, number of coils deployed per patient, and percentage of vessel occlusion obtained. A 0.015-inch-diameter regular coil and a 0.014-inch-diameter soft coil were used. RESULTS: A total of 1,061 coils were used; 1,009 were detached. The number of coils deployed ranged from four to 104 (mean, 17 coils). The coils passed easily through the microcatheter. The detachment maneuver occurred within 5-25 seconds, with five to 60 turns of the introducing wire. One premature coil detachment occurred without clinical sequela; 100% occlusion of the vessel lumen was achieved in 53 patients; 80%-90%, in four; and 70%-80%, in two. There were no device-related complications. CONCLUSION: The detachment system was safe and reliable. This is a useful system for coil embolization in neurovascular diseases.

Adult↗

PubMed2001

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.

Adult↗

PubMed2001

[Advances in the contributions of imaging to stereotaxic localization of cerebral arteriovenous malformations for radiosurgery ].

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.

Angiography, Digital Subtraction↗

PubMed2000

[Monitoring jugular venous oxygen saturation in severe cerebral vasospasm after subarachnoid hemorrhage].

Cerebral arterial vasospasm is a major complication of aneurysmal subarachnoid haemorrhage. The conventional treatment of this complication includes haemodilution, hypervolaemia, arterial hypertension and nimodipine. Some patients do not respond to this therapy and require an intraarterial infusion of papaverine and/or a cerebral angioplasty. Transcranial Doppler detects cerebral vasospasm. However it does not provide an accurate metabolic information on the ischaemic status of the cerebral tissue. This article describes the monitoring of jugular venous bulb oxygen saturation to obtain a real time information on the metabolic effect of cerebral vasospasm and its variations after intra-arterial infusion of papaverine.

Adult↗

PubMed2000

Developmental dyslexia: atypical cortical asymmetries and functional significance.

Using brain magnetic resonance imaging, we measured in 16 young developmental dyslexic adults and 14 age-matched controls cortical asymmetries of posterior language-related areas, including Planum temporale and parietal operculum cortical ribbon, and of the inferior frontal region related in the left hemisphere to speech processing. In addition, we assessed the sulcal morphology of the inferior frontal gyrus in both groups according to a qualitative method. The dyslexic subjects also performed specific tasks exploring different aspects of phonological and lexical-semantic processes. Results showed that: (1) contrary to most results reported in the literature, there is a lack of any morphological difference relative to Planum temporale asymmetry between the two groups; (2) there are significant differences between dyslexic and control subjects relative to frontal areas; (3) concerning the parietal region, there is a more asymmetrical pattern towards the left side in dyslexic subjects than in controls; and (4) relations in dyslexic subjects between parietal asymmetry coefficient and the level of performance in a phonological task have a particular reliance on verbal short-term memory, frontal asymmetry and performance in a non-word reading task. Considering these results it is suggested that phonological segmentation skills may relate to frontal lobe morphology, while phonological memory-based impairment in people with dyslexia may rather relate to parietal lobe morphology.

Adult↗

PubMed1999

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.

Adult↗