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Postmortem fetal magnetic resonance imaging (PMFMRI) is increasingly used thanks to its good overall concordance with histology paralleling the rising incidence of parental refusal of autopsy. The technique could become a routine clinical examination but it needs to be standardized and conducted by trained radiologists. Such radiologists should be aware of not only the (congenital and acquired) anomalies that can involve the fetus, but also of the “physiological” postmortem changes. In this article, we intend to focus on the contribution of PMFMRI based on the existing literature and on our own experience, as we presently perform the technique routinely in our clinical practice. Key Points • Concordance rates between PMFMRI and autopsy are high for detecting fetal pathologies. • PMFMRI is more acceptable for parents than traditional autopsy. • PMFMRI is becoming widely used as a part of the postmortem investigations. • A dedicated radiologist needs to learn to interpret correctly a PMFMRI. • PMFMRI can be easily realized in daily clinical practice.

BACKGROUND AND PURPOSE: Objective and quantitative data to define cerebellar vermis and/or brain stem hypoplasia in children are lacking. Our aim was to provide MR imaging biometric references for the cerebellar vermis and brain stem from a large cohort of children with normal cerebellums. MATERIALS AND METHODS: The MR imaging data were retrospectively selected from our hospital data base from January 1, 2014, to December 31, 2017. All MR imaging examinations of children between 1 day and 15 years of age, including midline sagittal sections, were included. Children with a clinical history or MR imaging abnormalities that may affect the posterior fossa were excluded. We manually measured four 2D parameters: vermian height, anterior-posterior diameter of the vermis, anterior-posterior diameter of the midbrain-pons junction, and anterior-posterior midpons diameter. The inter- and intraobserver agreement was evaluated. RESULTS: Seven hundred eighteen children were included (372 boys and 346 girls), from 1 day to 15 years of age. Normal values (third to 97th percentiles) were provided for each parameter. The vermis parameters showed a rapid growth phase during the first year, a slower growth until the fifth year, and finally a near-plateau phase. The brain stem parameters showed more progressive growth. The intra- and interobserver agreement was excellent for all parameters. CONCLUSIONS: We provide reference biometric data of the vermis and the brain stem using simple and reproducible measurements that are easy to use in daily practice. The relevance of these 2D measurements should be further validated in diseases associated with cerebellar abnormalities.

Summary Background and purpose Cerebral sinovenous thrombosis (CSVT) represents an increasingly recognized cause of pediatric stroke. Our purpose was to assess gender and age differences in the etiology, clinical presentation, and imaging features of CSVT in neonates and older children. Methods Subjects aged newborn to 18 years diagnosed with CSVT at the Lille university hospital between 2011 and 2014 were included. Results Eleven neonates and 16 non-neonates constituted the study population. The incidence of CSVT was significantly higher in male newborns. Clinical presentation did not vary significantly between the groups. Risk factors were age-dependent, with acute systemic illnesses significantly predominating in neonates (54%), whereas local infections, prothrombotic conditions, and trauma were more common in older children (36, 27, and 27% respectively). No predisposing factor could be identified in 36% of the neonates as compared to less than 5% of the non-neonates. Thrombosis of the deep venous structures was documented in 73% of the neonates whereas involvement of the superficial sinuses was significantly more frequent in the non-neonates group. Venous infarctions and extraparenchymal hemorrhages were significantly more frequent in the neonates group. Conclusion Male patients are at higher risk for CSVT than females. In neonates, involvement of the deep venous structures is significantly more common. Brain parenchymal and extraparenchymal changes occur more frequently in this age group than in older children.

In the case of ventriculomegaly in the elderly, it is often difficult to differentiate between communicating chronic hydrocephalus (CCH) and brain atrophy. The aim of this study is to describe the MRI criteria of CCH, defined by a symptomatic patient with ventriculomegaly and that improved after shunt placement.Magnetic resonance imaging was prospectively evaluated in 90 patients with ventriculomegaly. Patients were classified into three groups: patients without clinical signs of CCH (control, n = 47), patients with CCH treated by shunt placement with clinical improvement (responders, n = 36), and patients with CCH treated using a shunt without clinical improvement (nonresponders, n = 7). MRI parameters of the two groups of interest (responders vs. controls) were compared.Compared with controls, Evans' index (p = 0.029), ventricular area (p0.01), and volume (p = 0.0001) were higher in the responders. In this group, the callosal angle was smaller (p ≤ 0.0001) and the aqueductal stroke volume (SVa) of CSF was higher (p ≤ 0.0001) than in controls. On the ROC curves, the optimal cut-off values for differentiating between responders and controls were a ventricular area33.5 cmOn suspicion of CCH, a large ventricular area, a small callosal angle, and an increased aqueductal stroke volume are important MRI arguments that can be associated with the clinical evaluation and dynamic testing of CSF to confirm the indication for a shunt.

International audience; PURPOSE: This study evaluates the correlation between injuries to deep gray matter nuclei, as quantitated by lesions in these nuclei on MR T2 Fast Spin Echo (T2 FSE) images, with 6-month neurological outcome after severe traumatic brain injury (TBI). MATERIALS AND METHODS: Ninety-five patients (80 males, mean age = 36.7y) with severe TBI were prospectively enrolled. All patients underwent a MR scan within the 45 days after the trauma that included a T2 FSE acquisition. A 3D deformable atlas of the deep gray matter was registered to this sequence; deep gray matter lesions (DGML) were evaluated using a semi-quantitative classification scheme. The 6-month outcome was dichotomized into unfavorable (death, vegetative or minimally conscious state) or favorable (minimal or no neurologic deficit) outcome. RESULTS: Sixty-six percent of the patients (63/95) had both satisfactory registration of the 3D atlas on T2 FSE and available clinical follow-up. Patients without DGML had an 89% chance (P = 0.0016) of favorable outcome while those with bilateral DGML had an 80% risk of unfavorable outcome (P = 0.00008). Multivariate analysis based on DGML accurately classified patients with unfavorable neurological outcome in 90.5% of the cases. CONCLUSION: Lesions in deep gray matter nuclei may predict long-term outcome after severe TBI with high sensitivity and specificity.

Langerhans cell histiocytosis (LCH) represents a disorder characterised by an abnormal accumulation of histiocytes in miscellaneous tissues. The bone is commonly affected, especially the flat bones, the spine and the long bones. Some lesions in children such as a “vertebra plana” or a solitary lytic lesion of the skull may be suggestive for LCH, whereas others can be confused with a malignant tumour or osteomyelitis. This pictorial essay presents the main usual and unusual skeletal manifestations observed in LCH. • Osseous involvement in children with LCH is very similar to that seen in multiple myeloma. • A solitary lytic lesion of the cranial vault is a typical radiographic finding of LCH. • A vertebra plana appearance in the spine is another typical radiographic finding. • Extensive signal intensity changes within bone marrow on MRI are a helpful sign for the diagnosis. • In long bones, endosteal scalloping may be responsible for a “budding appearance”.

Background Existing methods to predict recovery after severe traumatic brain injury lack accuracy. The aim of this study is to determine the prognostic value of quantitative diffusion tensor imaging (DTI). Methods In a multicenter study, the authors prospectively enrolled 105 patients who remained comatose at least 7 days after traumatic brain injury. Patients underwent brain magnetic resonance imaging, including DTI in 20 preselected white matter tracts. Patients were evaluated at 1 yr with a modified Glasgow Outcome Scale. A composite DTI score was constructed for outcome prognostication on this training database and then validated on an independent database (n=38). DTI score was compared with the International Mission for Prognosis and Analysis of Clinical Trials Score. Results Using the DTI score for prediction of unfavorable outcome on the training database, the area under the receiver operating characteristic curve was 0.84 (95% CI: 0.75-0.91). The DTI score had a sensitivity of 64% and a specificity of 95% for the prediction of unfavorable outcome. On the validation-independent database, the area under the receiver operating characteristic curve was 0.80 (95% CI: 0.54-0.94). On the training database, reclassification methods showed significant improvement of classification accuracy (P < 0.05) compared with the International Mission for Prognosis and Analysis of Clinical Trials score. Similar results were observed on the validation database. Conclusions White matter assessment with quantitative DTI increases the accuracy of long-term outcome prediction compared with the available clinical/radiographic prognostic score.

We aimed to assess brain regional glucose uptake (rGlcU) changes in children with isolated cerebellar cortical dysplasia (CCD) using 18-fluoro-deoxy-glucose positron emission tomography (FDG-PET). Six children aged 9 months to 11 years at the time of diagnosis, carrying isolated CCD (with no other associated posterior fossa or supratentorial malformation) underwent a brain FDG-PET and a subsequent 3DT1-weighted MRI for coregistration. The MRIs acquired previously at the time of diagnosis were reviewed to record the cerebellar dysplastic features and classify the patients as having minor, moderate, or severe CCD. The individual rGlcU was assessed qualitatively on coregistrated FDG maps. Clinical data from birth, including neurological and neuropsychological (verbal and motor skills) disturbances, were recorded. We found rGlcU changes within the cerebellum of four patients matching with the location and extent of structural abnormalities: hypometabolism in three patients with severe CCD involving the vermis and both cerebellar hemispheres and focal hypermetabolism in one patient with moderate CCD associated with a nodular heterotopic gray matter. No obvious rGlcU changes were found in the two patients with minor CCD involving the vermis only. Supratentorial rGlcU changes found commonly involved the basal ganglia bilaterally. Coregistrated FDG-PET/MRI technique is useful in detecting cerebellar cell dysfunction associated with isolated CCD. Our results enhance the need for multimodal and quantitative studies to better evaluate local and remote functional disturbances caused by CCD.

Pediatric Moyamoya disease is rarely associated with intracranial aneurysms. We report a case of a 7-year-old girl with an antecedent of persistent craniopharyngeal canal, who presented with a history of choreiform movements. A Moyamoya disease was found with an unruptured left middle cerebral artery aneurysm on her first angiography. Conservative treatment was chosen for the aneurysm and she underwent indirect revascularization by encephalosynangiosis using the multiple bur-hole technique for her Moyamoya disease. Abnormal movements were improved. Control angiogram at 6 months showed development of intracranial–extracranial anastomoses with complete resolution of the aneurysm. Aneuryms including the major arteries of the basal arterial circle occur as a by-product of the high velocity and blood flow secondary to the arterial stenosis. Blood flow modification after revascularization often lead to spontaneous regression and disappearance of these aneurysms. Therefore, a conservative treatment of these proximal aneurysms must be chosen after encephalosynangiosis.

Diffusion-weighted magnetic resonance (MR) imaging (DWI), and three-dimensional (3D) time-of-flight (TOF) MR angiography (MRA), are highly sensitive for the early detection of stroke and arterial occlusion. However, only a few studies have evaluated the sensitivity of conventional MR sequences that are usually included in the imaging protocol. The aim of this study was to evaluate interobserver and intertechnique reproducibility of Fluid-Attenuated Inversion Recovery (FLAIR) sequences for the diagnosis of early brain ischemia and arterial occlusion.Over a 30-month period, brain MR examinations were performed in 34 patients within 12 hours after stroke onset. Imaging protocol included FLAIR sequences, DWI and 3D TOF MRA. Ten observers including radiologists and neurologists, performed separately a visual interpretation of FLAIR images for the detection of brain ischemia and arterial occlusion seen as an arterial high signal. DWI and 3D TOF MRA were used as reference and interpreted independently by two senior radiologists. Interobserver agreement was assessed for image quality, detectability and conspicuity of lesions whereas intertechnique agreement was only judged for lesion detectability.On FLAIR sequences, interobserver agreement for the detection of brain ischemia and arterial occlusion was excellent (kappa = 0.81 and 0.87 respectively). The concordance between FLAIR and DWI sequences for the detection of brain ischemia and between FLAIR and 3D TOF MRA for the detection of arterial occlusion were judged as excellent for all observers (kappa = 0.91 and 0.89 respectively).Although DWI is the most sensitive technique with which to detect acute stroke, FLAIR imaging may also be useful to demonstrate both acute ischemia and arterial occlusion with an excellent interobserver reproducibility.

Cavernous hemangioma is increasingly recognized as a late complication of cerebral irradiation (CI); however, the significance of the problem, especially the risk of hemorrhage, is not documented in the literature. In order to discover this, we reviewed our experience of radiation-induced cavernous hemangiomas (RICH) in patients who had received CI during childhood. We reviewed retrospectively our pediatric database of 965 brain tumors, 419 of which were irradiated between 1964 and 2003. We collected nine cases of RICH diagnosed in patients who had received CI during childhood. The CI dosage ranged between 25 and 55 Gy. The interval between CI and the diagnosis of RICH ranged from 4 to 22 years. The RICH was the cause of brain hemorrhage in five cases, three of which required surgical evacuation. Radiation-induced cavernous hemangiomas are an underestimated problem, and systematic screening of irradiated patients with gradient-echo MRI will probably yield more asymptomatic cases. We think that not all RICH require surgery, but only those responsible for intracerebral hemorrhage or that show radiological progression. With respect for the long interval between CI and diagnosis of RICH, we advise control with MRI, including gradient-echo sequence, as late as 15 years after CI, and closer monitoring of asymptomatic RICH.

Neuroimaging evaluation in patients after a first seizure could be easily determined on the basis of seizure history, neurological examination, blood sample analysis and electroencephalography. The main objectives of the initial work-up are to differentiate a true seizure event from seizure-like symptoms, to exclude a single seizure as a manifestation of non organic cause and finally to consider the seizure as a result of cerebral lesion or inaugurate epilepsy. When a new onset seizure is diagnosed, urgent neuroimaging is recommended only in patients with focal neurological deficit, persistent or worsening alteration in the level of consciousness and when clinical and biological data lead to a suspected vascular or infectious etiology. Brain CT scan is usually more available in emergency to identify the cause of seizure. It may have an important role for the therapeutic strategy and may defer MRI investigation. Nevertheless, brain MRI must be performed in emergency when CT scan is not conclusive despite a severe clinical condition or in case of cerebral venous thrombosis. Imaging modalities depend on clinical data, patient age and suspected epilepsy type.

Neuroimaging techniques including structural magnetic resonance imaging (MRI) and functional positron emission tomography (PET) are useful in categorizing various midbrain-hindbrain (MHB) malformations, both in allowing diagnosis and in helping to understand the developmental processes that were disturbed. Brain imaging phenotypes of numerous malformations are characteristic features that help in guiding the genetic testing in case of direct neuroimaging-genotype correlation or, at least, to differentiate among MHB malformations entities. The present review aims to provide the reader with an update of the use of neuroimaging applications in the fine analysis of MHB malformations, using a comprehensive, recently proposed developmental and genetic classification. We have performed an extensive systematic review of the literature, from the embryology main steps of MHB development through the malformations entities, with regard to their molecular and genetic basis, conventional MRI features, and other neuroimaging characteristics. We discuss disorders in which imaging features are distinctive and how these features reflect the structural and functional impairment of the brain. Recognition of specific MRI phenotypes, including advanced imaging features, is useful to recognize the MHB malformation entities, to suggest genetic investigations, and, eventually, to monitor the disease outcome after supportive therapies.

Chediak-Higashi syndrome is a rare inherited metabolic disorder characterized by partial oculocutaneous albinism, immunodeficiency, and neurological dysfunction. We present the brain magnetic resonance imaging (MRI) and MR spectroscopy (MRS) findings obtained during the accelerated phase of the disorder in an 8-year-old. The brain MRI manifestations at recurrences 15 months and 24 months later are reported as well.

We describe CT and MR findings in a 23-month-old infant with a melanotic neuroectodermal tumour of the pineal gland. The tumour has been stereotactically biopsied and surgically resected. The pathological diagnosis was made on the resected piece. Embryology of the pineal gland and the histology of melanotic neuroectodermal tumour of infancy are discussed.

Object: The purpose of this study was to describe late neuropathological MRI findings in pediatric severe head injury and to explore the relationship between these lesions and cognitive sequelae. Methods: Thirteen infants with severe head trauma (Glasgow 6) were included in this investigation. Clinical examination, a battery of tests designed to assess neurophysiological status, and MRI investigations of the brain were obtained in periods ranging between 8 and 20 months after the accident. Hemosiderin deposits, encephalomalacia, and cerebellar atrophy were the most frequent traumatic sequelae. The lesions were located in frontal lobes, the basal ganglia, and the cerebellum. Six patients had cerebellar atrophy associated with frontal or temporal postraumatic lesions. Cerebellar clinical dysfunction was observed in only 3 of these patients. Performance on tests evaluating frontal lobe functions was depressed in 5 of them. Conclusions: Late MRI after severe head trauma in our pediatric population showed unexpected cerebellar atrophy. Its correlation with prefrontal dysfunction is difficult to confirm because of its association with other parenchymal post-traumatic lesions. Further research involving a larger sample of patients with brain injury of varying severity is in progress, to investigate whether cerebellar atrophy could be a consequence of severe head trauma.

Cerebellar gliomas (CGs) in children are generally associated with a favorable outcome; however, data regarding these tumors in very young children are scarce. We report on our experience with CGs in children less than 3 years old at surgery, compared with a second group older than 3 years. From 1991 to 1996, we operated on 7 children with CGs in the first group and 43 in the second. Psychomotor delay and regression were the first symptoms in 3 cases, and 3 had macrocrania. The tumor was totally removed in all cases. One child died intraoperatively of air embolism and subdural bleeding. Three had malignant tumors (grade 3 or 4). There was no operative mortality or malignancy in the second group of patients. With a mean follow-up of 33 months, all survivors in the first group are disease-free, with no or minimal symptoms, and attend normal schools. The clinical, surgical, and pathological features suggest that children under 3 years of age represent a specific subgroup of CGs.

International audience; BACKGROUND: Existing methods to predict recovery after severe traumatic brain injury lack accuracy. The aim of this study is to determine the prognostic value of quantitative diffusion tensor imaging (DTI). METHODS: In a multicenter study, the authors prospectively enrolled 105 patients who remained comatose at least 7 days after traumatic brain injury. Patients underwent brain magnetic resonance imaging, including DTI in 20 preselected white matter tracts. Patients were evaluated at 1 yr with a modified Glasgow Outcome Scale. A composite DTI score was constructed for outcome prognostication on this training database and then validated on an independent database (n=38). DTI score was compared with the International Mission for Prognosis and Analysis of Clinical Trials Score. RESULTS: Using the DTI score for prediction of unfavorable outcome on the training database, the area under the receiver operating characteristic curve was 0.84 (95% CI: 0.75-0.91). The DTI score had a sensitivity of 64% and a specificity of 95% for the prediction of unfavorable outcome. On the validation-independent database, the area under the receiver operating characteristic curve was 0.80 (95% CI: 0.54-0.94). On the training database, reclassification methods showed significant improvement of classification accuracy (P < 0.05) compared with the International Mission for Prognosis and Analysis of Clinical Trials score. Similar results were observed on the validation database. CONCLUSIONS: White matter assessment with quantitative DTI increases the accuracy of long-term outcome prediction compared with the available clinical/radiographic prognostic score.

To describe neuropsychological disturbances and the developmental course associated with cerebellar cortical dysplasia (CCD).The neuroimaging findings from 10 children (five males, five females; aged 3-10 y) with CCD were reviewed and classified. These children all underwent clinical neurological examination and neuropsychological assessment (NPA) on admission, then were followed for an average of 6 years using the cognitive Wechsler Scale, Vineland Adaptive Behavior Scales, and Rey-Osterrieth Complex Figure/McCarthy Drawing subtests.Based on magnetic resonance imaging, CCD was categorized as minor (n = 4), moderate (n = 1), and severe (n = 5). The first NPA disclosed mental retardation* in six (profound, three; moderate, one; mild, two) and normal intelligence in four (low, two; average, one; high, one), but with verbal/performance dissociation in three cases. Socio-adaptive functions were altered in all children except one. Visuospatial abilities were delayed in eight children. In the follow-up, no progression was observed in the three cases with profound mental retardation, whereas the remainder showed homogeneous or disharmonic progression, including improvement or deterioration of verbal/performance function. Cognitive impairment and evolution was not associated with the degree of cerebellar involvement.The neuropsychological profile and evolution associated with CCD do not appear to be predictable, and some features might improve over time.

Object The aim of this paper was to measure the posterior fossa (PF) volume increase resulting from a given-sized occipital craniectomy in Chiari malformation Type I surgery and to analyze its correlations with the PF size and the treatment response, with the perspective of tailoring the amount of bone removal to the patient-specific PF dimensions. Methods Between January 2005 and June 2006, 11 adult patients with symptomatic Chiari malformation Type I underwent a standardized PF decompression. A prospective evaluation with clinical examination, functional grading, and MR imaging measurement protocols was performed pre- and postoperatively. A method is reported for the measurement of PF volume (PFV) after surgery. The degree of PFV increase was compared with the preoperative size of the PF and with the clinical outcome. Results All 11 patients improved postoperatively, with complete and partial recovery in 4 and 7 patients, respectively. No postoperative complication occurred after a mean follow-up period of 45 months. The mean relative increase in PFV accounted for 10% (range 1.5%–19.7%) of the initial PFV; the increase was greater in cases in which the PF was small (r = −0.52, p = 0.09) and the basiocciput was short (r = −0.37, p = 0.2). A statistically significant positive correlation was found between the degree of PFV increase and the treatment response (p = 0.014); complete recovery was observed with a PFV increase of 15% and partial recovery with an increase of 7%. Conclusions The treatment response is significantly influenced by the degree of PFV increase, which is dependent on the size of the PF and the extent of the craniectomy, suggesting that the optimal patient-specific PFV increase could be predicted on the basis of preoperative MR imaging and enhancing the perspective that the craniectomy size could be tailored to the individual PFV.

A newborn suffered immediate neonatal respiratory distress because of an obstructive, soft-tissue nasal mass. Clinical examination revealed a cleft palate with a protruding polypoid mass. CT and MRI showed a heterogeneous nasopharyngeal mass and associated intracranial abnormalities - duplication of the hypophysis and hypoplasia of the corpus callosum. Duplication of the hypophysis is a very rare malformation, only 13 cases having been previously described. The suggested pathogenesis is duplication of the prechordal plate and anterior end of the notochord during early embryological development.

Spinal cord compression due to meningeal thickening is a rare occurrence in shunted patients. Because of the long delay to clinical onset, this complication has not been identified as yet. We report on nine cases of shunt-related progressive myelopathy due to meningeal thickening (SPMMT). We reviewed our database of shunted children, for cases having developed progressive tetraparesis due to cervical meningeal thickening. We identified nine observations of SPMMT, eight of these with hydrocephalus due to neonatal meningitis; the last case had Dandy–Walker malformation shunted at birth and suffered postoperative meningitis. The age of clinical onset of myelopathy was between 6 and 20 years (median 12.8). All patients presented with slowly progressive walking difficulties with falls and no spinal pain. Magnetic resonance imaging (MRI) showed typically a thickened dura mater with collapse of the arachnoid space, compensatory expansion of the epidural fat, and T2 hyperintensity in the spinal cord. We operated on seven patients for surgical decompression and arachnoidolysis: One died postoperatively because of shunt malfunction, and two others died later of complications of tetraplegia. Three patients were aggravated after surgery, three experienced partial improvement, but one of these subsequently deteriorated again. SPMMT appears to be a novel and well-defined clinical and pathological entity; its pathological and radiological features are stereotyped; however, the diagnosis is delayed because of the slow pace of the disease. Although surgical decompression may be the only option, its results were poor in our experience; earlier surgery might improve this grim prognosis.

The dating of inflicted head injuries in infants is a recurrent and difficult problem in the forensic evaluation of child abuse. The dating of hemorrhagic lesions when using magnetic resonance (MR) imaging is delicate because many confusing factors interact. In particular, infants frequently develop subdural hematomas (SDHs), which are generally composed of a supernatant, similar to cerebrospinal fluid (CSF), and a sediment, similar to blood clots. In the absence of a validated theoretical model predicting the evolution of blood signal in head-injured infants, clinical data are much needed; however, reliably dated information regarding head injuries in infants is scarce.The authors prospectively studied infants who presented with dated and corroborated head injury to investigate the temporal modifications of computerized tomography (CT) and MR imaging in relation to the delay since trauma. In cases of SDH, the authors distinguished between sediment and supernatant based on their CT scanning appearance. They then studied the MR imaging signal of these two components in T1- and T2-weighted, fluid-attenuated inversion recovery (FLAIR), and gradient-echo sequences. Whereas the signal of the supernatant showed little difference from that of the CSF and did not yield information about the date of trauma, the signal in the sediment, especially on the T1-weighted and FLAIR sequences, showed time-related modifications that could be used to date the trauma.The authors propose a method by which to develop a time scale for the dating of head injuries in infants based on the modifications of signal and location of blood on CT and MR images.

In mental retardation (MR) an aetiological diagnosis is not always obtained despite a detailed history, physical examination and metabolic or genetic investigations. In some of these patients, MRI is recommended and may identify subtle abnormal brain findings. We reviewed the cerebral MRI of children with non-specific mental retardation in an attempt to establish a neuroanatomical picture of this disorder. Thirty children with non-specific MR were selected to undergo cerebral MRI. The examination included supratentorial axial slices, mid-sagittal images and posterior fossa coronal images. Brain malformations, midline and cerebellar abnormalities were studied. In 27 of 30 patients, the neuroimaging evaluation revealed a relatively high incidence of cerebral and posterior fossa abnormalities. The most frequent were: dysplasia of the corpus callosum (46%; hypoplasia, short corpus callosum and vertical splenium), partially opened septum pellucidum and/or cavum vergae (33%), ventriculomegaly (33%), cerebral cortical dysplasia (23%), subarachnoid space enlargement (16.6%), vermian hypoplasia (33%), cerebellar and/or vermian disorganised folia (20%), and subarachnoid spaces enlargement in the posterior fossa (20%). Other anomalies were: enlarged Virchow-Robin spaces (10%), white matter anomalies (10%) and cerebellar or vermian atrophy. MRI has shown a high incidence of subtle cerebral abnormalities and unexpected minor forms of cerebellar cortical dysplasia. Even if most of these abnormalities are considered as subtle markers of brain dysgenesis, their role in the pathogenesis of mental retardation needs further investigation.

OBJECTIVES AND DESIGN: We performed a prospective study using magnetic resonance imaging (MRI) at regular post-operative intervals in non-irradiated patients with non-functioning pituitary adenomas (NFAs) to assess the frequency of tumoral regrowth and recurrences, in order to define the indications of post-operative radiotherapy. PATIENTS AND METHODS: Fifty-one patients aged 25--80 years (mean, 55.6plus minus12.3 years) were included. Post-operative MRIs were performed 3--12 months (mean, 5.2plus minus1.7 months) after surgery, 6 months later and then, every 12--18 months for at least 2 years. The mean post-operative follow-up was 67.7plus minus31.8 months (range, 24--144 months). RESULTS: In 17 patients (33%, group I) no tumoral residue was observed on post-operative MRIs and no tumoral recurrence was diagnosed. Tumour regrowth was detected in 13 of the 34 patients (38.2%) with post-operative tumoral residue (group II), 7--66 months (mean, 27.3plus minus17.3 months) after surgery. In this group, Kaplan--Meier analysis showed 78.8% recurrence free survival at 2 years and 60.9% at 5 years. Patients with tumoral regrowth had higher mean residual tumoral volume than patients without any tumoral regrowth in the group II (258plus minus165 vs 163plus minus165 mm(3), P=0.05). CONCLUSIONS: We suggest a MRI protocol that includes, a 4- to 6-, 12- and 24-month post-operative MRI for every patient. When no tumoral residue is seen, pituitary radiotherapy is useless. MRI must be repeated 3, 5 and 10 years after surgery to eliminate late recurrence. The observed frequency of tumoral regrowth in patients with tumoral residue does not justify systematic post-operative radiotherapy. It should be performed only when tumoral regrowth is proved by a yearly MRI survey.

The clinical and pathological characteristics of supratentorial ependymomas (STE) in children are not well identified in the literature, because most series deal with ependymomas regardless of their location or the age of the patient. As a result, the pathological description of the disorder is still debated. We therefore reviewed our cases of children operated for STE and compared them with cases of infratentorial ependymomas (ITE) to provide a better characterization of STE and suggest guidelines for treatment. From 1985 to 1999, we operated 18 children for STE, almost half of which developed with no connection to the ventricular system. Intraoperative bleeding and infiltration of the basal ganglia prevented total removal in 4 cases and were the main causes of operative mortality and morbidity. The 5-year overall survival and recurrence-free survival rates were 54 and 37%, respectively, and were highly affected by the extent of resection, but not by histological grade. Because of the high recurrence rate, we recommend systematic postoperative irradiation limited to the tumor site for all high-grade tumors in older children, and reoperation after subtotal removal and for recurrences.