Three-dimensional rotational angiography in the assessment of the angioarchitecture of brain arteriovenous malformations.

BACKGROUND AND PURPOSE: The angioarchitecture of brain arteriovenous malformations (BAVM) still remains a complex subject of study despite advances in medical imaging techniques. For this reason, the present study aimed to assess whether or not 3D rotational angiography (3DXA) might improve the assessment of BAVM. PATIENTS AND METHODS: Included prospectively were 72 patients who had undergone conventional digital subtraction angiography (DSA) and 3DXA for pretherapeutic assessment of BAVM prior to radiosurgery. Dimensional criteria, arterial-feed patterns, venous drainage, points of weakness and vascular densities (VD) of the nidus and shunt zone were studied. RESULTS: 3DXA detected all arteriovenous shunts by revealing abnormal venous enhancement. Post-processing tools similar to CT and MRI may also be used to make complex 3D reconstructions. In addition, the technique provided significant help for volumetric estimations, extraction of arterial feeders and origins of draining veins, and analysis of the 3D conformation of the nidus. Furthermore, 3DXA detected significantly more points of weakness, such as intranidus aneurysms and venous anomalies (P<0.005). In 65% of cases, a gradient of vascular enhancement intensity was found between the arteries and draining veins surrounding or comprising the nidus. VD, or the percentages of space occupied by the enhanced vascular elements, was evaluated in both the nidus and shunt zone. VD in the shunt zone was highest in untreated patients with no history of bleeding (P<0.005). CONCLUSION: 3DXA offers a useful approach to BAVM exploration and can improve our knowledge of lesional angioarchitecture, necessary for the planning of therapeutic strategies.

[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. Analysis of eight consecutive patients]. / Traitement endovasculaire de l'hypertension intracrânienne bénigne étiquetée "idiopathique". Analyse de huit cas consécutifs.

INTRODUCTION: Optic nerve sheath fenestration or ventricular shunting are classically proposed after failure of medical treatment. 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. PATIENTS AND METHOD: Between September 2003 and December 2004, eight consecutive patients with a diagnosis of idiopathic intracranial hypertension underwent MRI venography and direct retrograde cerebral angiography. RESULTS: There were five females and three males aged 22 to 55 years. All patients had vision disorders. The cerebrospinal fluid pressure ranged from 27 to 45 mmHg with normal composition. All patients presented at least one sinus stenosis. Endovascular stenting of the stenotic venous sinus was performed under intravenous heparin administration. Anti-platelet therapy was administered for 3 months post treatment. Intra-sinus pressures were invariably reduced by stenting. Mean follow-up was 18 months. All patients improved clinically. The cerebrospinal fluid pressure had normalized at 3-month follow-up in all patients. In all patients, multidetector row CT-angiography or MRI venography was performed at 3-, 6- and 12-month follow-up and demonstrated the patency of the stent. DISCUSSION: The importance of venous sinus disease as a cause of idiopathic intracranial hypertension is probably underestimated. Patients with idiopathic intracranial hypertension should be evaluated with direct retrograde cerebral venography and manometry. In patients with venous sinus lesions, treatment by an endoluminal venous sinus stent is a safe and effective alternative for amenable lesions.

[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.

[Endovascular treatment of benign intracranial hypertension by stent placement in the transverse sinus. Therapeutic and pathophysiological considerations illustrated by a case report]. / Traitement endovasculaire d'un syndrome d'hypertension intracrânienne bénigne par mise en place d'un stent dans le sinus lateral. Considerations thérapeutiques et physiopathologiques à propos d'un cas.

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.

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.

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.

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.

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.

Diverging asymmetries of temporo-parietal cortical areas: a reappraisal of Geschwind/Galaburda theory.

The general theory on the biological foundations of cerebral dominance formulated in 1985 by Geschwind and Galaburda entirely relies on a postulated causal relationship between anatomical asymmetry of the planum temporale and functional lateralization of the human brain, but does not take into account asymmetry of another cortical region, the parietal operculum. In 40 normal volunteers whose handedness was specified by the Edinburgh Handedness Inventory, we assessed asymmetries of these two regions on MRI sagittal scans. For both measurements, a significantly larger leftward asymmetry was found in the 24 consistent right-handers compared to the 16 non-right-handers. Moreover, the combination, for each subject, of the two indices of asymmetry, yielded four different subtypes between which handedness distribution significantly differed. We conclude that planum temporale and parietal operculum asymmetries may be divergent and that their convergence is strongly associated with right-handedness. Functional and developmental implications of these findings are discussed by reference to the Geschwind/Galaburda theory.

[Acute myelopathies in young patients and multiple sclerosis. prospective study of 20 cases]. / Myélopathies aiguës du sujet jeune et sclérose en plaques. Etude prospective de 20 cas.

The risk of progression to multiple sclerosis (MS) after an episode of acute non compressive episode involving the spinal cord remains uncertain. A follow-up study was performed to determine the risk of early progression to MS in 20 patients presenting with clinically isolated lesions of the spinal cord, combined clinical evaluation, spinal and brain magnetic resonance imaging (MRI), visual, brainstem auditory and somatosensory evoked potentials (VEPs, BAEPs, SEPs), and cerebrospinal fluid (CSF) electrophoresis analysis. Spinal cord MRI demonstrated more lesions in cervical region (74 p. 100) than thoracic or lumbar regions (26 p. 100). Six patients (30 p. 100) had an initial brain MRI that was strongly suggestive of MS and 5 patients (25 p. 100) had only one MS-like abnormality. Eight patients (40 p. 100) had abnormal VEPs, 3 (15 p. 100) abnormal BAEPSs and only 44 p. 100 (8/18) abnormal SEPs. In contrast, CSF analysis showed oligoclonal bands (CSFOB) in 15/19 patients (79 p. 100). The diagnosis of MS was performed initially in 13 cases (65 p. 100) (clinically definite MS (CDMS) in 30 p. 100, laboratory-supported definite MS (LSDMS) in 61 p. 100 and clinically probable (CPMS) in one case). During the follow-up period (18 +/- 7 months), 8 patients (40 p. 100) presented one or more exacerbations and time to the first recurrence was 8 +/- 5 months. Seven of these 8 patients were initially treated by infusion of methylprednisolone. Among these patients, all of them had CSF OB and initial brain MRI was strongly suggestive of MS in 3 of them. During this follow-up period, brain MRI showed emergence of lesions in 4 cases with normal initial examination and 3 of them presented exacerbations. At the follow-up term, the diagnosis of MS was performed in 15 cases (75 p. 100) CDMs in 66 p. 100, LSDMS in 26 p. 100 and CPMS in one case). This confirms the predictive value of brain MRI and CSF OB for the diagnosis of MS in patients who present with clinically isolated acute syndrome of the spinal cord.

[Reflex epilepsy with seizures induced by mental calculation, playing chess and scrabble]. / Epilepsie réflexe avec crises induites par le calcul mental, le jeu d'échecs et le jeu de scrabble.

Reflex seizures induced by higher mental activity is rare. We report the case of a young man with myoclonic jerks and generalized tonico-clonic convulsion precipitated by calculation, playing chess and scrabble. Routine EEG, including hyperventilation and photic stimulation, showed no abnormality. Tests stimulation procedures, including spatial tasks, induced focal and generalized EEG spike-wave complex and myoclonic jerks. Valproate was effective in reducing epileptic seizures during a follow-up period of three years. Comparison of our case with previously reported reflex epilepsy with seizures induced by higher mental activity is discussed.

[Angiodysplasia of moya-moya type disclosed by choreic unvoluntary abnormal movements during oral contraception. Apropos of 2 cases]. / Angiodysplasie de type Moya-Moya révélée par des mouvements anormaux involontaires choréiformes au cours d'une contraception orale. A propos de 2 cas.

Two seventeen year-old women, developed acute onset left choreic movements following two months and two weeks use of oral contraceptives. Left hemiparesia appeared a few days later, while involuntary movements discontinued. Cranial CT scan and MRI showed bilateral ischemic lesion in the frontal region for the first case and isolated lesion in the right centrum ovale for the second. Angiography showed nearly complete obstruction of the terminal portion of the internal carotid artery with an outline Moya-Moya network. After discontinuing oral contraceptives, there has been no relapse of neurologic dysfunction for more than three years for the first case and twelve months for the second one. The role of perfusion insufficiency in limb-shaking carotid transient ischemic attack is discussed and the possible relations between oral contraceptives, chorea and angiographic features resembling Moya-Moya disease are evaluated.

Value of MRI in the morphological evaluation of tumors of the third ventricle.

The detection or suspicion of a tumoral expansive process in the third ventricule is usually performed by MRI. The contribution of MRI to the diagnosis is unquestionable in view of its accuracy in the topographical characterization of these lesions and in the detection of small formations. The great histological variety of tumours in that region may result in different treatments which can be associated. MRI, therefore, plays an important role in pretherapeutic morphological evaluation. Fifteen patients with tumour of the third ventricle were examined by MRI before treatment. The results of these examinations were compared with the pathological data and the therapeutic procedures: ventricular shunting, stereotactic needle biopsy, radio- or chemotherapy and surgery. MRI cannot provide a formal histological characterization, but it can individualise some categories of tumours, give details on the walls of the third ventricle (notably in the case of bifocal pineal and suprassellar lesions), visualize the paths of CSF flow and predict the need for cisternoventriculostomy, and detect venous structures in the vicinity of the great cerebral vein which might result in post-biopsy and post-surgery complications.

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.

[Functional cerebral neuro-imaging at 1.5 Tesla. The results of visual, sensorimotor and auditory stimulations]. / Neuro-imagerie fonctionnelle cérébrale à 1,5 Tesla. Résultats de stimulations visuelles, sensitivo-motrices et auditives.

Functional activation of the cerebral cortex can be observed with a standard 1.5 Tesla MRI magnet. We used a repeated FLASH 2D one-section sequence with a long echo (TE = 60 ms) and a small passing band. Modification of regional cerebral oxygenation due to neurone activation seems to be the main source of contrast. Sensorimotor stimulation was effected by an unusual mobilization of the fingers. Visual stimulation was performed by intermittent lightings at a frequency of 8 Hz. Auditory stimulation relied on listening to speech sounds. Signal increases were localized on the cerebral cortex with precise anatomico-functional correlation. Using a clinical 1.5 Tesla magnet requires an adequate treatment of data. Thus, stimulated cerebral activity can be portrayed by MRI therapy opening a new way for anatomico-functional cerebral studies.

[Monitoring jugular venous oxygen saturation in severe cerebral vasospasm after subarachnoid hemorrhage]. / Monitorage de la saturation veineuse jugulaire en oxygène au cours d'un vasospasme cérébral sévère après hémorragie sous-arachnoïdienne.

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.

[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.

[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.

[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.