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Head of department of Neuroradiology
Timone University Hospital (APHM)
tel: 33 4 91 38 65 25
fax: 33 4 91 38 68 33

Key Words
- Brain maturation
- Fetal brain
- Pediatric brain tumors
- Diffusion imaging
- Perfusion
- Spectroscopy

Current Research Interest and projects

- Fractional anisotropy of fetal cortex
- Perfusion (DSC) in pediatric brain tumors
- Gyrification of the fetal brain with computational softwares
- Gyrification in autism



Journal Article

  • Tuleasca, C, Najdenovska, E, Régis, J, Witjas, T, Girard, N, Champoudry, J, Faouzi, M, Thiran, J-P, Bach Cuadra, M, Levivier, M & Van De Ville, D 2018, “Pretherapeutic functional neuroimaging predicts tremor arrest after thalamotomy”, Acta Neurologica Scandinavica.
    Résumé : OBJECTIVE: Essential tremor (ET) represents the most common movement disorder. Drug-resistant ET can benefit from standard stereotactic procedures (deep brain stimulation or radiofrequency thalamotomy) or alternatively minimally invasive high-focused ultrasound or radiosurgery. All aim at same target, thalamic ventro-intermediate nucleus (Vim). METHODS: The study included a cohort of 17 consecutive patients, with ET, treated only with left unilateral stereotactic radiosurgical thalamotomy (SRS-T) between September 2014 and August 2015. The mean time to tremor improvement was 3.32 months (SD 2.7, 0.5-10). Neuroimaging data were collected at baseline (n = 17). Standard tremor scores, including activities of daily living (ADL) and tremor score on treated hand (TSTH), were completed pretherapeutically and 1 year later. We further correlate these scores with baseline inter-connectivity in twenty major large-scale brain networks. RESULTS: We report as predictive three networks, with the interconnected statistically significant clusters: primary motor cortex interconnected with inferior olivary nucleus, bilateral thalamus interconnected with motor cerebellum lobule V2 (ADL), and anterior default-mode network interconnected with Brodmann area 103 (TSTH). For all, more positive pretherapeutic interconnectivity correlated with higher drop in points on the respective scores. Age, disease duration, or time-to-response after SRS-T were not statistically correlated with pretherapeutic brain connectivity measures (P > .05). The same applied to pretherapeutic tremor scores, after using the same methodology described above. CONCLUSIONS: Our findings have clinical implications for predicting clinical response after SRS-T. Here, using pretherapeutic magnetic resonance imaging and data processing without prior hypothesis, we show that pretherapeutic network(s) interconnectivity strength predicts tremor arrest in drug-naïve ET, following stereotactic radiosurgical thalamotomy.
    Mots-clés : fMRI, Resting state, snc, thalamotomy.

  • Tuleasca, C, Najdenovska, E, Régis, J, Witjas, T, Girard, N, Champoudry, J, Faouzi, M, Thiran, J-P, Cuadra, MB, Levivier, M & Van De Ville, D 2018, “Clinical response to Vim's thalamic stereotactic radiosurgery for essential tremor is associated with distinctive functional connectivity patterns”, Acta Neurochirurgica, vol. 160, no. 3, p. 611-624.
    Résumé : INTRODUCTION: Essential tremor (ET) is the most common movement disorder. Drug-resistant ET can benefit from standard surgical stereotactic procedures (deep brain stimulation, thalamotomy) or minimally invasive high-intensity focused ultrasound (HIFU) or stereotactic radiosurgical thalamotomy (SRS-T). Resting-state fMRI (rs-fMRI) is a non-invasive imaging method acquired in absence of a task. We examined whether rs-fMRI correlates with tremor score on the treated hand (TSTH) improvement 1 year after SRS-T. METHODS: We included 17 consecutive patients treated with left unilateral SRS-T in Marseille, France. Tremor score evaluation and rs-fMRI were acquired at baseline and 1 year after SRS-T. Resting-state data (34 scans) were analyzed without a priori hypothesis, in Lausanne, Switzerland. Based on degree of improvement in TSTH, to consider SRS-T at least as effective as medication, we separated two groups: 1, ≤ 50% (n = 6, 35.3%); 2, > 50% (n = 11, 64.7%). They did not differ statistically by age (p = 0.86), duration of symptoms (p = 0.41), or lesion volume at 1 year (p = 0.06). RESULTS: We report TSTH improvement correlated with interconnectivity strength between salience network with the left claustrum and putamen, as well as between bilateral motor cortices, frontal eye fields and left cerebellum lobule VI with right visual association area (the former also with lesion volume). Longitudinal changes showed additional associations in interconnectivity strength between right dorsal attention network with ventro-lateral prefrontal cortex and a reminiscent salience network with fusiform gyrus. CONCLUSIONS: Brain connectivity measured by resting-state fMRI relates to clinical response after SRS-T. Relevant networks are visual, motor, and attention. Interconnectivity between visual and motor areas is a novel finding, revealing implication in movement sensory guidance.
    Mots-clés : fMRI, Independent component analysis, radiosurgery, resting-state, snc, thalamotomy, ventro-intermediate nucleus.

  • Tuleasca, C, Najdenovska, E, Régis, J, Witjas, T, Girard, N, Champoudry, J, Faouzi, M, Thiran, J-P, Cuadra, MB, Levivier, M & Van De Ville, D 2018, “Ventro-lateral motor thalamus abnormal connectivity in essential tremor before and after thalamotomy: a resting-state fMRI study”, World Neurosurgery.
    Résumé : OBJECTIVE: To evaluate functional connectivity (FC) of the ventro-lateral thalamus, a common target for drug-resistant essential tremor (ET), resting-state data were analyzed before and 1 year after stereotactic radiosurgical thalamotomy (SRS-T), and compared against healthy controls (HC). METHODS: 17 consecutive patients and 10 HC were enrolled. Tremor network was investigated using ventro-lateral ventral (VLV) nucleus as region-of-interest (ROI), extracted using automated segmentation from pretherapeutic diffusion MRI. Temporal correlations of VLV at whole brain level were evaluated by comparing drug-naïve ET with HC, and longitudinally, 1 year after SRS-T. Thalamotomy volume was always located inside VLV, and did not correlate with any of FC measures (p>0.05). This suggested presence of longitudinal changes in VLV FC independently of thalamotomy volume. RESULTS: Pretherapeutic ET displayed altered VLV FC with left primary sensory-motor cortex, pedunculopontine nucleus, dorsal anterior cingulate, left visual association and left superior parietal areas. Pretherapeutic negative FC with primary somatosensory cortex and pedunculopontine nucleus correlated with poorer baseline tremor scores (Spearmann=0.04 and 0.01). Longitudinal study displayed changes within right dorsal attention (frontal eye-fields and posterior parietal) and salience (anterior insula) networks, as well as areas involved in hand movement planning or language production. CONCLUSION: Our results demonstrated that ET and HC differ in their VLV FC to primary somatosensory and supplementary motor, visual association, or brainstem areas (pedunculopontine nucleus). Longitudinal changes display reorganization of dorsal attention and salience networks after thalamotomy. Beside attentional gateway, they are also known for their major role in facilitating a rapid access to the motor system.
    Mots-clés : fMRI, motor thalamus, resting-state, snc, thalamotomy, ventro-intermediate nucleus.

  • Tuleasca, C, Régis, J, Najdenovska, E, Witjas, T, Girard, N, Champoudry, J, Faouzi, M, Thiran, J-P, Cuadra, MB, Levivier, M & Van De Ville, D 2018, “Pretherapeutic Functional Imaging Allows Prediction of Head Tremor Arrest After Thalamotomy for Essential Tremor: The Role of Altered Interconnectivity Between Thalamolimbic and Supplementary Motor Circuits”, World Neurosurgery.
    Résumé : OBJECTIVE: To correlate pretherapeutic resting-state functional magnetic resonance imaging (rs-fMRI) measures with pretherapeutic head tremor presence and/or further improvement 1 year after stereotactic radiosurgical thalamotomy (SRS-T) for essential tremor (ET). METHODS: We prospectively collected head tremor scores (range, 0-3) and rs-fMRI data for a cohort of 17 consecutive ET patients in pretherapeutic and 1 year after SRS-T states. We additionally acquired rs-fMRI data for a healthy control (HC) group (n = 12). Group-level independent component analysis (n = 17 for pretherapeutic rs-fMRI) was applied to decompose neuroimaging data into 20 large-scale brain networks using a standard approach. Through spatial regression, we projected 1 year after SRS-T and HC rs-fMRI time points, on the same 20 brain networks. RESULTS: Pretherapeutic interconnectivity (IC) strength between the network including bilateral thalamus and limbic system with left supplementary motor area predicted head tremor improvement at 1 year after SRS-T (family-wise corrected P < 0.001, cluster size Kc = 146). For the statistically significant cluster, IC strength was strongest in HCs (mean, 4.6; median, 3.8) compared with pre- (mean, 0.1; median, 0.2) or posttherapeutic (mean, -0.2; median, 0.09) states. CONCLUSIONS: Baseline measures of IC between bilateral thalamus and limbic system with left supplementary motor area may predict head tremor arrest after thalamotomy. However, procedures such as SRS-T, for this particular clinical feature, do not align patients to HCs in terms of functional brain connectivity. We postulate that supplementary motor area is modulating head tremor appearance, by abnormal connectivity with the thalamolimbic system.
    Mots-clés : fMRI, Head tremor, Resting state, snc, thalamotomy, Ventrointermediate nucleus.

  • Tuleasca, C, Régis, J, Najdenovska, E, Witjas, T, Girard, N, Thiran, J-P, Bach Cuadra, M, Levivier, M & Van De Ville, D 2018, “Visually-sensitive networks in essential tremor: evidence from structural and functional imaging”, Brain: A Journal of Neurology.

  • Tuleasca, C, Witjas, T, Van de Ville, D, Najdenovska, E, Verger, A, Girard, N, Champoudry, J, Thiran, J-P, Cuadra, MB, Levivier, M, Guedj, E & Régis, J 2018, “Right Brodmann area 18 predicts tremor arrest after Vim radiosurgery: a voxel-based morphometry study”, Acta Neurochirurgica, vol. 160, no. 3, p. 603-609.
    Résumé : INTRODUCTION: Drug-resistant essential tremor (ET) can benefit from open standard stereotactic procedures, such as deep-brain stimulation or radiofrequency thalamotomy. Non-surgical candidates can be offered either high-focused ultrasound (HIFU) or radiosurgery (RS). All procedures aim to target the same thalamic site, the ventro-intermediate nucleus (e.g., Vim). The mechanisms by which tremor stops after Vim RS or HIFU remain unknown. We used voxel-based morphometry (VBM) on pretherapeutic neuroimaging data and assessed which anatomical site would best correlate with tremor arrest 1 year after Vim RS. METHODS: Fifty-two patients (30 male, 22 female; mean age 71.6 years, range 49-82) with right-sided ET benefited from left unilateral Vim RS in Marseille, France. Targeting was performed in a uniform manner, using 130 Gy and a single 4-mm collimator. Neurological (pretherapeutic and 1 year after) and neuroimaging (baseline) assessments were completed. Tremor score on the treated hand (TSTH) at 1 year after Vim RS was included in a statistical parametric mapping analysis of variance (ANOVA) model as a continuous variable with pretherapeutic neuroimaging data. Pretherapeutic gray matter density (GMD) was further correlated with TSTH improvement. No a priori hypothesis was used in the statistical model. RESULTS: The only statistically significant region was right Brodmann area (BA) 18 (visual association area V2, p = 0.05, cluster size Kc = 71). Higher baseline GMD correlated with better TSTH improvement at 1 year after Vim RS (Spearman's rank correlation coefficient = 0.002). CONCLUSIONS: Routine baseline structural neuroimaging predicts TSTH improvement 1 year after Vim RS. The relevant anatomical area is the right visual association cortex (BA 18, V2). The question whether visual areas should be included in the targeting remains open.


Journal Article

  • Mace, P, Milh, M, Girard, N, Sigaudy, S & Quarello, E 2017, “[How to deal with a fetal head circumference lower than the third percentile?]”, Gynecologie, Obstetrique, Fertilite & Senologie, vol. 45, no. 9, p. 491-511.
    Résumé : The prenatal finding of a head circumference (HC) below the 3rd percentile (p) remains, in the same way as short femur or increased nuchal translucency with normal karyotype, one the most difficult situations for the praticionner in the setting of prenatal diagnosis. Microcephaly is a gateway to possible cerebral pathologies, but the main objective is to identify serious prenatal situations. A standardized HC measurement, the use of adapted reference tools and charts, longitudinal following of cephalic biometrics in high-risk situations, and systematic central nervous system analysis can increase the diagnostic performance of ultrasound which is often disappointing for microcephaly. The early distinction between associated or isolated microcephaly makes it possible to quickly orient the prenatal management and counseling. Fetal MRI and genetic counseling are fundamental in this context, making it possible to specify at best the etiological diagnosis and to provide assistance to the neuropediatrician in the establishment of an often uncertain prognosis. The recent increase in cases of microcephaly concomitant with the epidemic of the ZIKA virus is an additional argument to improve our practices and the daily apprehension of HC<3rd p.

  • Tuleasca, C, Witjas, T, Najdenovska, E, Verger, A, Girard, N, Champoudry, J, Thiran, J-P, Van de Ville, D, Cuadra, MB, Levivier, M, Guedj, E & Régis, J 2017, “Assessing the clinical outcome of Vim radiosurgery with voxel-based morphometry: visual areas are linked with tremor arrest!”, Acta Neurochirurgica, vol. 159, no. 11, p. 2139-2144.
    Résumé : INTRODUCTION: Radiosurgery (RS) is an alternative to open standard stereotactic procedures (deep-brain stimulation or radiofrequency thalamotomy) for drug-resistant essential tremor (ET), aiming at the same target (ventro-intermediate nucleus, Vim). We investigated the Vim RS outcome using voxel-based morphometry by evaluating the interaction between clinical response and time. METHODS: Thirty-eight patients with right-sided ET benefited from left unilateral Vim RS. Targeting was performed using 130 Gy and a single 4-mm collimator. Neurological and neuroimaging assessment was completed at baseline and 1 year. Clinical responders were considered those with at least 50% improvement in tremor score on the treated hand (TSTH). RESULTS: Interaction between clinical response and time showed the left temporal pole and occipital cortex (Brodmann area 19, including V4, V5 and the parahippocampal place area) as statistically significant. A decrease in gray matter density (GMD) 1 year after Vim RS correlated with higher TSTH improvement (Spearman = 0.01) for both anatomical areas. Higher baseline GMD within the left temporal pole correlated with better TSTH improvement (Spearman = 0.004). CONCLUSIONS: Statistically significant structural changes in the relationship to clinical response after Vim RS are present in remote areas, advocating a distant neurobiological effect. The former regions are mainly involved in locomotor monitoring toward the local and distant environment, suggesting the recruiting requirement in targeting of the specific visuomotor networks.


Journal Article

  • Koob, M, Girard, N, Ghattas, B, Fellah, S, Confort-Gouny, S, Figarella-Branger, D & Scavarda, D 2016, “The diagnostic accuracy of multiparametric MRI to determine pediatric brain tumor grades and types”, Journal of Neuro-Oncology, vol. 127, no. 2, p. 345-353.
    Résumé : Childhood brain tumors show great histological variability. The goal of this retrospective study was to assess the diagnostic accuracy of multimodal MR imaging (diffusion, perfusion, MR spectroscopy) in the distinction of pediatric brain tumor grades and types. Seventy-six patients (range 1 month to 18 years) with brain tumors underwent multimodal MR imaging. Tumors were categorized by grade (I-IV) and by histological type (A-H). Multivariate statistical analysis was performed to evaluate the diagnostic accuracy of single and combined MR modalities, and of single imaging parameters to distinguish the different groups. The highest diagnostic accuracy for tumor grading was obtained with diffusion-perfusion (73.24 %) and for tumor typing with diffusion-perfusion-MR spectroscopy (55.76 %). The best diagnostic accuracy was obtained for tumor grading in I and IV and for tumor typing in embryonal tumor and pilocytic astrocytoma. Poor accuracy was seen in other grades and types. ADC and rADC were the best parameters for tumor grading and typing followed by choline level with an intermediate echo time, CBV for grading and Tmax for typing. Multiparametric MR imaging can be accurate in determining tumor grades (primarily grades I and IV) and types (mainly pilocytic astrocytomas and embryonal tumors) in children.
    Mots-clés : Brain Neoplasms, Child, crmbm, Diffusion Magnetic Resonance Imaging, Magnetic Resonance Angiography, Magnetic Resonance Spectroscopy, snc.

  • Koob, M, Rousseau, F, Laugel, V, Meyer, N, Armspach, J-P, Girard, N & Dietemann, J-L 2016, “Cockayne Syndrome: A Diffusion Tensor Imaging and Volumetric Study”, The British Journal of Radiology, p. 20151033.
    Résumé : OBJECTIVES: Cockayne syndrome (CS) is a rare disorder characterized by severe brain atrophy, white matter hypomyelination, and basal ganglia calcifications. This study aimed to quantify atrophy and white matter abnormalities using diffusion tensor imaging (DTI) and volumetric analysis, to evaluate possible differences between CS subtypes, and to determine if DTI findings may correspond to a hypomyelinating disorder. METHODS: Fourteen CS patients and 14 controls underwent brain MRI including DTI and a volumetric 3D T1-weighted sequence. DTI analysis was made through ROIs within the whole brain to obtain fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values, and in the left centrum semiovale to obtain DTI eigenvalues. A Student's t-test was used to compare patients and controls, and CS subtypes. Given the small number of CS patients, they were pooled in two groups: moderate (CS1/CS3) and severe (CS2/COFS (cerebro-oculo-facio-skeletal syndrome)). RESULTS: Total brain volume in CS was reduced by 57%, predominantly in the infratentorial area (68%) (p <0.001). Total brain volume reduction was greater in the severe group, but there was no difference in the degree of infratentorial atrophy in the two groups (p = 0.7). Mean FA values were lower, whereas ADC was higher in most of the white matter in CS patients (p <0.05). ADC in the splenium of the corpus callosum and the posterior limb of the internal capsule, and FA in the cerebral peduncles were significantly different between the two groups (p <0.05). Mean ADC values corresponded to a hypomyelinating disorder. All DTI eigenvalues were higher in CS patients, mainly for transverse diffusivity (+51%) (p <0.001). CONCLUSIONS: DTI and volumetric analysis provide quantitative information for the characterization of CS, and may be particularly useful for evaluating therapeutic intervention. ADVANCES IN KNOWLEDGE: DTI combined with volumetric analysis provides additional informations useful not only for characterization of Cockayne syndrome and distinction of clinical subtypes but also to monitor therapeutic interventions.
    Mots-clés : snc.

  • Tallinen, T, Chung, JY, Rousseau, F, Girard, N, Lefevre, J & Mahadevan, L 2016, “On the growth and form of cortical convolutions”, Nature Physics, vol. 12, no. 6, p. 588-593.
    Résumé : The rapid growth of the human cortex during development is accompanied by the folding of the brain into a highly convoluted structure(1-3). Recent studies have focused on the genetic and cellular regulation of cortical growth(4-8), but understanding the formation of the gyral and sulcal convolutions also requires consideration of the geometry and physical shaping of the growing brain(9-15). To study this, we use magnetic resonance images to build a 3D-printed layered gel mimic of the developing smooth fetal brain; when immersed in a solvent, the outer layer swells relative to the core, mimicking cortical growth. This relative growth puts the outer layer into mechanical compression and leads to sulci and gyri similar to those in fetal brains. Starting with the same initial geometry, we also build numerical simulations of the brain modelled as a soft tissue with a growing cortex, and show that this also produces the characteristic patterns of convolutions over a realistic developmental course. All together, our results show that although many molecular determinants control the tangential expansion of the cortex, the size, shape, placement and orientation of the folds arise through iterations and variations of an elementary mechanical instability modulated by early fetal brain geometry.
    Mots-clés : brain size, evolution, folding pattern, gyrification, malformations, mammalian cerebral-cortex, mechanical model, ontogeny, snc, tangential expansion.


Journal Article

  • Auzias, G, Viellard, M, Takerkart, S, Villeneuve, N, Poinso, F, Fonséca, DD, Girard, N & Deruelle, C 2014, “Atypical sulcal anatomy in young children with autism spectrum disorder”, NeuroImage. Clinical, vol. 4, p. 593-603.
    Résumé : Autism spectrum disorder is associated with an altered early brain development. However, the specific cortical structure abnormalities underlying this disorder remain largely unknown. Nonetheless, atypical cortical folding provides lingering evidence of early disruptions in neurodevelopmental processes and identifying changes in the geometry of cortical sulci is of primary interest for characterizing these structural abnormalities in autism and their evolution over the first stages of brain development. Here, we applied state-of-the-art sulcus-based morphometry methods to a large highly-selective cohort of 73 young male children of age spanning from 18 to 108 months. Moreover, such large cohort was selected through extensive behavioral assessments and stringent inclusion criteria for the group of 59 children with autism. After manual labeling of 59 different sulci in each hemisphere, we computed multiple shape descriptors for each single sulcus element, hereby separating the folding measurement into distinct factors such as the length and depth of the sulcus. We demonstrated that the central, intraparietal and frontal medial sulci showed a significant and consistent pattern of abnormalities across our different geometrical indices. We also found that autistic and control children exhibited strikingly different relationships between age and structural changes in brain morphology. Lastly, the different measures of sulcus shapes were correlated with the CARS and ADOS scores that are specific to the autistic pathology and indices of symptom severity. Inherently, these structural abnormalities are confined to regions that are functionally relevant with respect to cognitive disorders in ASD. In contrast to those previously reported in adults, it is very unlikely that these abnormalities originate from general compensatory mechanisms unrelated to the primary pathology. Rather, they most probably reflect an early disruption on developmental trajectory that could be part of the primary pathology.

  • Koob, M & Girard, N 2014, “Cerebral tumors: specific features in children”, Diagnostic and Interventional Imaging, vol. 95, no. 10, p. 965-983.
    Résumé : Brain tumors are the second leading cause of cancer in children. Primary tumors predominate and are of very varied histological types. Their prognosis and treatment depend on the histological type and grade. The diagnostic approach to these includes analysis of the site of the lesion and appearances on computed tomography and MR, and taking account of the age and clinical features of the child. CT is used to diagnose the tumor in an emergency situation. Conventional MR provides a morphological approach and allows a staging assessment to be carried out before surgery. Advanced MR techniques (diffusion-weighted and perfusion imaging, MR spectroscopy) provide further information for the differential diagnosis, presumptive diagnosis of type and grade and to guide biopsy towards the most malignant areas in the lesion.


Journal Article

  • Fellah, S, Caudal, D, De Paula, AM, Dory-Lautrec, P, Figarella-Branger, D, Chinot, O, Metellus, P, Cozzone, PJ, Confort-Gouny, S, Ghattas, B, Callot, V & Girard, N 2013, “Multimodal MR imaging (diffusion, perfusion, and spectroscopy): is it possible to distinguish oligodendroglial tumor grade and 1p/19q codeletion in the pretherapeutic diagnosis?”, AJNR. American journal of neuroradiology, vol. 34, no. 7, p. 1326-1333.
    Résumé : BACKGROUND AND PURPOSE: Pretherapeutic determination of tumor grade and genotype in grade II and III oligodendroglial tumors is clinically important but is still challenging. Tumor grade and 1p/19q status are currently the 2 most important factors in therapeutic decision making for patients with these tumors. Histopathology and cMRI studies are still limited in some cases. In the present study, we were interested in determining whether the combination of PWI, DWI, and MR spectroscopy could help distinguish oligodendroglial tumors according to their histopathologic grade and genotype. MATERIALS AND METHODS: We retrospectively reviewed 50 adult patients with grade II and III oligodendrogliomas and oligoastrocytomas who had DWI, PWI, and MR spectroscopy at short and long TE data and known 1p/19q status. Univariate analyses and multivariate random forest models were performed to determine which criteria could differentiate between grades and genotypes. RESULTS: ADC, rCBV, rCBF, and rK2 were significantly different between grade II and III oligodendroglial tumors. DWI, PWI, and MR spectroscopy showed no significant difference between tumors with and without 1p/19q loss. Separation between tumor grades and genotypes with cMRI alone showed 31% and 48% misclassification rates, respectively. Multimodal MR imaging helps to determine tumor grade and 1p/19q genotype more accurately (misclassification rates of 17% and 40%, respectively). CONCLUSIONS: Although multimodal investigation of oligodendroglial tumors has a lower contribution to 1p/19q genotyping compared with cMRI alone, it greatly improves the accuracy of grading of these neoplasms. Use of multimodal MR imaging could thus provide valuable information that may assist clinicians in patient preoperative management and treatment decision making.
    Mots-clés : Adolescent, Adult, Aged, Aged, 80 and over, Astrocytoma, Brain Neoplasms, Cerebral Cortex, Chromosomes, Human, Pair 1, Chromosomes, Human, Pair 19, Contrast Media, crmbm, Diagnosis, Differential, Diffusion Magnetic Resonance Imaging, Female, Frontal Lobe, Genotype, Humans, Image Enhancement, Image Processing, Computer-Assisted, Magnetic Resonance Angiography, Magnetic Resonance Imaging, Magnetic Resonance Spectroscopy, Male, Middle Aged, Neoplasm Grading, Oligodendroglioma, Retrospective Studies, Sequence Deletion, Temporal Lobe, Young Adult.


Journal Article

  • Fellah, S, Callot, V, Viout, P, Confort-Gouny, S, Scavarda, D, Dory-Lautrec, P, Figarella-Branger, D, Cozzone, PJ & Girard, N 2012, “Epileptogenic brain lesions in children: the added-value of combined diffusion imaging and proton MR spectroscopy to the presurgical differential diagnosis”, Child's nervous system: ChNS: official journal of the International Society for Pediatric Neurosurgery, vol. 28, no. 2, p. 273-282.
    Résumé : PURPOSE: Focal cortical dysplasia (FCD), dysembryoplastic neuroepithelial tumors (DNTs), and gangliogliomas (GGs) share many clinical features, and the presurgical differential diagnosis of these lesions using conventional magnetic resonance imaging (MRI) is challenging in some cases. The purpose of this work was thus to evaluate the capacity of diffusion-weighted imaging (DWI) and proton magnetic resonance spectroscopy (MRS) to distinguish each lesion from the others. METHODS: Seventeen children (mean age 9.0 ± 4.7 years), who had been referred for epilepsy associated with a brain tumor and operated, were selected. Preoperative MRI examinations were performed on a 1.5 T system and included anatomical images [T2-weighted, fluid-attenuated inversion recovery (FLAIR) and T1 pre- and post-injection images] as well as DWI and MRS [echo time (TE) = 30 and 135 ms]. Apparent diffusion coefficient (ADC) values were calculated in the lesion and healthy control. MRS relative quantification consisted in normalizing each metabolite by the sum (S) of all metabolites (S(TE=135 ms) = NAA+Cr+Cho; S(TE=30 ms) = NAA+Cr+Cho+Glx+mI). Univariate and multivariate analyses were performed in order to determine which criteria could differentiate the different epileptogenic brain lesions. RESULTS: When taken alone, none of the MRI parameters was able to distinguish each disease from the others. Conventional MRI failed classifying two patients. When adding ADC to the linear discriminant analysis (LDA), one patient was still misclassified. Complete separation of the three groups was possible when combining conventional MRI, diffusion, and MRS either at long or short TE. CONCLUSION: This study shows the added-value of multimodal MRI and MRS in the presurgical diagnosis of epileptogenic brain lesions in children.
    Mots-clés : Adolescent, Brain Diseases, Brain Neoplasms, Child, Child, Preschool, crmbm, Diagnosis, Differential, Diffusion Magnetic Resonance Imaging, Epilepsy, Humans, Infant, Magnetic Resonance Spectroscopy, Malformations of Cortical Development, Malformations of Cortical Development, Group I, Protons.


Journal Article

  • Fellah, S, Girard, N, Chinot, O, Cozzone, PJ & Callot, V 2011, “Early evaluation of tumoral response to antiangiogenic therapy by arterial spin labeling perfusion magnetic resonance imaging and susceptibility weighted imaging in a patient with recurrent glioblastoma receiving bevacizumab”, Journal of clinical oncology: official journal of the American Society of Clinical Oncology, vol. 29, no. 11, p. e308-311.
    Mots-clés : Aged, Antibodies, Monoclonal, Antibodies, Monoclonal, Humanized, Antineoplastic Combined Chemotherapy Protocols, Brain Neoplasms, Camptothecin, crmbm, Fatal Outcome, Glioblastoma, Humans, Magnetic Resonance Angiography, Male, Neoplasm Recurrence, Local, Spin Labels.

  • Girard, NJ 2011, “Magnetic resonance imaging of fetal developmental anomalies”, Topics in magnetic resonance imaging: TMRI, vol. 22, no. 1, p. 11-23.
    Résumé : Fetal developmental anomalies consist of central nervous system malformations, brain injury, and tumors. Overlap is often seen especially between malformation and injury because malformation may be genetically determined or related to external causative agent, whereas brain injury may be, on one hand, caused by malformation as with intracranial vascular malformation and, on another, can cause brain malformation when cerebral insult occurs during organogenesis and histogenesis. The goal of this review was not to describe by magnetic resonance imaging (MRI) all fetal developmental anomalies encountered in utero; it is most likely to focus on fetal brain anomalies that either are most commonly seen in fetal tertiary care facility or are extremely challenging for MRI. Consequently, the potential of advanced MR techniques such as proton MR spectroscopy and diffusion tensor imaging is also described especially when a challenge is highlighted. This review is therefore organized in subchapters as follows. The first section gives the place of MRI in prenatal development and cites the standard protocol and the advanced techniques. The rules of fetal brain MRI, the challenge and pitfalls, and the selection of MRI cases follow as 3 subchapters. Also, abnormalities are described as 3 separate subchapters entitled ventriculomegalies (hydrocephalus), malformations, and brain injury.
    Mots-clés : Brain, Brain Diseases, Developmental Disabilities, Female, Humans, Infant, Newborn, Magnetic Resonance Imaging, Male, Malformations of Cortical Development, Prenatal Diagnosis.

  • Viola, A, Confort-Gouny, S, Schneider, JF, Le Fur, Y, Viout, P, Chapon, F, Pineau, S, Cozzone, PJ & Girard, N 2011, “Is brain maturation comparable in fetuses and premature neonates at term equivalent age?”, AJNR. American journal of neuroradiology, vol. 32, no. 8, p. 1451-1458.
    Résumé : BACKGROUND AND PURPOSE: Improved knowledge of brain maturation in fetuses and premature neonates is crucial for the early detection of pathologies and would help determine whether MR data from the premature brain might be used to evaluate fetal maturation. Using diffusion-weighted MR imaging and (1)H-MR spectroscopy, we compared cerebral microstructure and metabolism in normal in utero fetuses imaged near term and premature neonates imaged at term equivalent. MATERIALS AND METHODS: Forty-eight subjects were investigated: 24 in utero fetuses (mean gestational age, 37 ± 1 weeks) and 24 premature neonates (mean postconceptional age, 37 ± 1 weeks). ADC values were measured in cerebellum, pons, white matter, brain stem, basal ganglia, and thalamus. MR spectroscopy was performed in deep white matter. RESULTS: Mean ADC values from fetuses and premature neonates were comparable except for the pons and the parietal white matter. ADC values were lower in the pons of premature neonates, whereas greater values were found in their parietal white matter compared with fetuses. Proton MR spectroscopy showed higher levels of NAA/H(2)O, Glx/H(2)O, tCr/H(2)O, and mIns/H(2)O in premature neonates compared with fetuses. CONCLUSIONS: Our study provides evidence of subtle anomalies in the parietal white matter of healthy premature neonates. In addition, the reduced ADC values in the pons together with the increased levels of NAA/H(2)O, tCr/H(2)O, and Glx/H(2)O in the centrum semiovale suggest a more advanced maturation in some white matter regions. Our results indicate that MR data from the premature brain are not appropriate for the assessment of the fetal brain maturation.
    Mots-clés : Brain, crmbm, Fetal Organ Maturity, Fetus, Gestational Age, Humans, Infant, Newborn, Infant, Premature, Term Birth.

  • Zanin, E, Ranjeva, J-P, Confort-Gouny, S, Guye, M, Denis, D, Cozzone, PJ & Girard, N 2011, “White matter maturation of normal human fetal brain. An in vivo diffusion tensor tractography study”, Brain and behavior, vol. 1, no. 2, p. 95-108.
    Résumé : We demonstrate for the first time the ability to determine in vivo and in utero the transitions between the main stages of white matter (WM) maturation in normal human fetuses using magnetic resonance diffusion tensor imaging (DTI) tractography. Biophysical characteristics of water motion are used as an indirect probe to evaluate progression of the tissue matrix organization in cortico-spinal tracts (CSTs), optic radiations (OR), and corpus callosum (CC) in 17 normal human fetuses explored between 23 and 38 weeks of gestation (GW) and selected strictly on minimal motion artifacts. Nonlinear polynomial (third order) curve fittings of normalized longitudinal and radial water diffusivities (Z-scores) as a function of age identify three different phases of maturation with specific dynamics for each WM bundle type. These phases may correspond to distinct cellular events such as axonal organization, myelination gliosis, and myelination, previously reported by other groups on post-mortem fetuses using immunostaining methods. According to the DTI parameter dynamics, we suggest that myelination (phase 3) appears early in the CSTs, followed by the OR and by the CC, respectively. DTI tractography provides access to a better understanding of fetal WM maturation.
    Mots-clés : crmbm.


Journal Article

  • Khalfa, S, Guye, M, Peretz, I, Chapon, F, Girard, N, Chauvel, P & Liégeois-Chauvel, C 2008, “Evidence of lateralized anteromedial temporal structures involvement in musical emotion processing”, Neuropsychologia, vol. 46, no. 10, p. 2485-2493.
    Résumé : The right and left anteromedial temporal lobes have been shown to participate in emotion processing. The aim of the study was to further address their role in music emotion perception/recognition, and assessment by two emotional determinants, i.e., arousal (relaxing versus stimulating aspects) and valence (pleasantness degree). Epileptic patients with right or left anterior mesio-temporal resection (including the amygdala), and control subjects were presented with happy musical (chosen highly stimulating) or sad excerpts (chosen to be relaxing), that were either consonant (pleasant) or dissonant (unpleasant). The patients demonstrated an abnormal perception of dissonant music disregarding of the side of the resection; thereby confirming the role of the parahippocampal gyrus in the perception of unpleasantness. Moreover, the pleasantness of musical excerpts, in particular the happy consonant ones, was overestimated by patients with right temporal damage. In contrast, the arousal rating for happy consonant excerpts was reduced only in the group with left-resections. This modified perception of arousal might be related to the decreased ability of those patients to recognize happy and sad music. Indeed, both right and left temporal resections impaired sadness recognition, whereas happiness recognition was only reduced by the left-resections. The main result was that for the first time, the mesio-temporal structures were demonstrated to be asymmetrically involved in positive musical emotion recognition.
    Mots-clés : Acoustic Stimulation, Adult, Analysis of Variance, Arousal, Emotions, Epilepsy, Temporal Lobe, Female, Functional Laterality, Humans, Imaging, Three-Dimensional, Male, Middle Aged, Music, Recognition (Psychology), Task Performance and Analysis, Temporal Lobe.


Journal Article
  • Galanaud, D, Nicoli, F, Confort-Gouny, S, Le Fur, Y, Dormont, D, Girard, N, Ranjeva, J & Cozzone, P 2007, “[Brain magnetic resonance spectroscopy]”, Journal de radiologie, vol. 88, no. 3 Pt 2, p. 483-496.
    Résumé : MR spectroscopy (MRS) sequences allow noninvasive exploration of brain metabolism during a MRI examination. Their day-to-day use in a clinical setting has recently been improved by simple programming of sequences and automated quantification of metabolites. However, a few simple rules should be observed in the choice of sequences and the location of the voxels so as to obtain an informative, high-quality examination. The research applications of MR spectroscopy, where use of this examination seeks to better understand the pathophysiology of the disease, must be distinguished from its clinical indications, where MRS provides information that can be used directly in patient management. The most significant of the clinical uses are imaging intracranial tumors (positive and differential diagnosis, extension, treatment follow-up), diffuse brain injury, encephalopathies (especially hepatic and HIV-related), and the diagnosis of metabolic disorders.
    Mots-clés : Adrenoleukodystrophy, Adult, Brain, Brain Diseases, Brain Diseases, Metabolic, Brain Injuries, Brain Neoplasms, Canavan Disease, Child, crmbm, Diagnosis, Differential, Female, Follow-Up Studies, Glioblastoma, Hepatic Encephalopathy, Humans, Magnetic Resonance Imaging, Magnetic Resonance Spectroscopy, Male, Middle Aged, Mitochondrial Diseases, Multiple sclerosis.
  • Galanaud, D, Nicoli, F, Confort-Gouny, S, Le Fur, Y, Ranjeva, JP, Viola, A, Girard, N & Cozzone, PJ 2007, “[Indications for cerebral MR proton spectroscopy in 2007]”, Revue neurologique, vol. 163, no. 3, p. 287-303.
    Résumé : Magnetic resonance spectroscopy (MRS) is being increasingly performed alongside the more conventional MRI sequences in the exploration of neurological disorders. It is however important to clearly differentiate its clinical applications aiming at improving the differential diagnosis or the prognostic evaluation of the patient, from the research protocols, when MRS can contribute to a better understanding of the pathophysiology of the disease or to the evaluation of new treatments. The most important applications in clinical practice are intracranial space occupying lesions (especially the positive diagnosis of intracranial abscesses and gliomatosis cerebri and the differential diagnosis between edema and tumor infiltration), alcoholic, hepatic, and HIV-related encephalopathies and the exploration of metabolic diseases. Among the research applications, MRS is widely used in multiple sclerosis, ischemia and brain injury, epilepsy and neuro degenerative diseases.
    Mots-clés : AIDS Dementia Complex, Brain, Brain Diseases, Brain Neoplasms, crmbm, Diagnosis, Differential, Humans, Magnetic Resonance Imaging, Magnetic Resonance Spectroscopy, Mitochondrial Myopathies, Nervous System Diseases.

  • McGonigal, A, Bartolomei, F, Régis, J, Guye, M, Gavaret, M, Trébuchon-Da Fonseca, A, Dufour, H, Figarella-Branger, D, Girard, N, Péragut, J-C & Chauvel, P 2007, “Stereoelectroencephalography in presurgical assessment of MRI-negative epilepsy”, Brain: a journal of neurology, vol. 130, no. Pt 12, p. 3169-3183.
    Résumé : According to most existing literature, the absence of an MRI lesion is generally associated with poorer prognosis in resective epilepsy surgery. Delineation of the epileptogenic zone (EZ) by intracranial recording is usually required but is perceived to be more difficult in 'MRI negative' cases. Most previous studies have used subdural recording and there is relatively less published data on stereoelectroencephalography (SEEG). The objective of this study was to report the experience of our group in using SEEG in presurgical evaluation, comparing its effectiveness in normal and lesional MRI cases. One hundred consecutive patients undergoing SEEG for presurgical assessment were studied. Forty-three patients out of one hundred (43%) had normal MRI and 57 (57%) had lesional MRI. Successful localization was achieved with no difference between these two groups, in 41/43 (95%) normal MRI and in 55/57 (96%) lesional MRI cases (P = 1.00). Surgery was proposed in 84/100 patients and contraindicated in 16/100 with no significant difference between lesional and MRI-negative groups (P > 0.05). At 1 year follow-up, 11/20 (55%) of those having undergone cortectomy in the MRI-negative group and 21/40 (53%) in the lesional MRI group were entirely seizure free (P > 0.05) and these proportions were maintained at 2 years follow-up. Significant improvement in seizure control (ILAE outcome groups 1-4) was achieved in >90% cases with no difference between groups (P > 0.05). Of MRI-negative cases that underwent surgery, 10/23 (43%) had focal cortical dysplasia. This series showed that SEEG was equally effective in the presurgical evaluation of MRI-negative and lesional epilepsies.
    Mots-clés : Adolescent, Adult, Brain Mapping, Child, Electroencephalography, Epilepsy, False Negative Reactions, Female, Humans, Magnetic Resonance Imaging, Male, Middle Aged, Patient Selection, Preoperative Care, Stereotaxic Techniques, Treatment Outcome.

  • Schneider, JF, Confort-Gouny, S, Le Fur, Y, Viout, P, Bennathan, M, Chapon, F, Fogliarini, C, Cozzone, P & Girard, N 2007, “Diffusion-weighted imaging in normal fetal brain maturation”, European radiology, vol. 17, no. 9, p. 2422-2429.
    Résumé : Diffusion-weighted imaging (DWI) provides information about tissue maturation not seen on conventional magnetic resonance imaging. The aim of this study is to analyze the evolution over time of the apparent diffusion coefficient (ADC) of normal fetal brain in utero. DWI was performed on 78 fetuses, ranging from 23 to 37 gestational weeks (GW). All children showed at follow-up a normal neurological evaluation. ADC values were obtained in the deep white matter (DWM) of the centrum semiovale, the frontal, parietal, occipital and temporal lobe, in the cerebellar hemisphere, the brainstem, the basal ganglia (BG) and the thalamus. Mean ADC values in supratentorial DWM areas (1.68 +/- 0.05 mm(2)/s) were higher compared with the cerebellar hemisphere (1.25 +/- 0.06 mm(2)/s) and lowest in the pons (1.11 +/- 0.05 mm(2)/s). Thalamus and BG showed intermediate values (1.25 +/- 0.04 mm(2)/s). Brainstem, cerebellar hemisphere and thalamus showed a linear negative correlation with gestational age. Supratentorial areas revealed an increase in ADC values, followed by a decrease after the 30th GW. This study provides a normative data set that allows insights in the normal fetal brain maturation in utero, which has not yet been observed in previous studies on premature babies.
    Mots-clés : Analysis of Variance, Brain, Brain Mapping, crmbm, Diffusion Magnetic Resonance Imaging, Female, Gestational Age, Humans, Pregnancy, Retrospective Studies.

  • Schneider, JF, Confort-Gouny, S, Viola, A, Le Fur, Y, Viout, P, Bennathan, M, Chapon, F, Figarella-Branger, D, Cozzone, P & Girard, N 2007, “Multiparametric differentiation of posterior fossa tumors in children using diffusion-weighted imaging and short echo-time 1H-MR spectroscopy”, Journal of magnetic resonance imaging: JMRI, vol. 26, no. 6, p. 1390-1398.
    Résumé : PURPOSE: To assess the combined value of diffusion-weighted imaging (DWI) and proton magnetic resonance spectroscopy (1H-MRS) in differentiating medulloblastoma, ependymoma, pilocytic astrocytoma, and infiltrating glioma in a pediatric population. MATERIALS AND METHODS: A total of 17 children with untreated posterior fossa tumors (seven medulloblastoma, four infiltrating glioma, two ependymoma, and four pilocytic astrocytoma), were investigated with conventional MRI, DWI, and MRS using a single-voxel technique. Within the nonnecrotic tumor core, apparent diffusion coefficient (ADC) values using a standardized region of interest (ROI) were retrieved. Quantification of water signal and analysis of metabolite signals from MRS measurements in the same tumorous area were reviewed using multivariant linear discriminant analysis. RESULTS: Combination of ADC values and metabolites, which were normalized using water as an internal standard, allowed discrimination between the four tumor groups with a likelihood below 1 x 10(-9). Positive predictive value was 1 in all cases. Tumors could not be discriminated when using metabolite ratios or ADC values alone, nor could they be differentiated using creatine (Cr) as an internal reference even in combination with ADC values. CONCLUSION: Linear discriminant analysis using DWI and MRS using water as internal reference, fully discriminates the four most frequent posterior fossa tumors in children.
    Mots-clés : Adolescent, Astrocytoma, Brain Neoplasms, Child, Child, Preschool, Cranial Fossa, Posterior, crmbm, Diagnosis, Differential, Diffusion Magnetic Resonance Imaging, Discriminant Analysis, Ependymoma, Female, Glioma, Humans, Infant, Magnetic Resonance Spectroscopy, Male, Medulloblastoma, Retrospective Studies, Statistics, Nonparametric.

  • Schneider, JF, Viola, A, Confort-Gouny, S, Ayunts, K, Le Fur, Y, Viout, P, Bennathan, M, Chapon, F, Figarella-Branger, D, Cozzone, P & Girard, N 2007, “Infratentorial pediatric brain tumors: the value of new imaging modalities”, Journal of neuroradiology. Journal de neuroradiologie, vol. 34, no. 1, p. 49-58.
    Résumé : The correct assessment of the four most frequent infratentorial brain tumors in children (medulloblastoma, ependymoma, pilocytic astrocytoma and infiltrating glioma) has always been problematic. They are known to often resemble one another on conventional magnetic resonance (MR) imaging. We tested the hypothesis whether the combined strength of diffusion-weighted imaging (DWI) and proton MR spectroscopy (MRS) could help differentiate these tumors. Seventeen children with untreated posterior fossa tumors were investigated between January 2005 and January 2006 with conventional MR imaging and combined DWI and MR spectroscopy using a single-voxel technique at short and long echo time (TE) of 30 ms and 135 ms respectively. Apparent diffusion coefficient (ADC) values were retrieved after regions of interest were manually positioned within non necrotic tumor core. Water signal was quantified and metabolite signals were compared and analyzed using linear discriminant analysis. When a combination of ADC values and normalized metabolites was used, all tumors could be discriminated against one other. This could only be achieved when metabolites were normalized using water as an internal standard. They could not be discriminated when using metabolite ratios or ADC values alone, nor could they be differentiated using creatine (Cr) as an internal reference even in combination with ADC values. In conclusion, linear discriminant analysis and multiparametric combination of DWI and MRS, although not replacing histology, fully discriminates the four most frequent posterior fossa tumors in children, but metabolites have to be normalized using water and not Cr signal as an internal reference.
    Mots-clés : Adolescent, Child, Child, Preschool, crmbm, Diffusion Magnetic Resonance Imaging, Female, Glioma, Humans, Infratentorial Neoplasms, Magnetic Resonance Spectroscopy, Male, Reproducibility of Results, Retrospective Studies.


Journal Article

  • Girard, N, Fogliarini, C, Viola, A, Confort-Gouny, S, Fur, YL, Viout, P, Chapon, F, Levrier, O & Cozzone, P 2006, “MRS of normal and impaired fetal brain development”, European journal of radiology, vol. 57, no. 2, p. 217-225.
    Résumé : Cerebral maturation in the human fetal brain was investigated by in utero localized proton magnetic resonance spectroscopy (MRS). Spectra were acquired on a clinical MR system operating at 1.5 T. Body phased array coils (four coils) were used in combination with spinal coils (two coils). The size of the nominal volume of interest (VOI) was 4.5 cm(3) (20 mm x 15 mm x 15 mm). The MRS acquisitions were performed using a spin echo sequence at short and long echo times (TE = 30 ms and 135 ms) with a VOI located within the cerebral hemisphere at the level of the centrum semiovale. A significant reduction in myo-inositol and choline and an increase in N-acetylaspartate were observed with progressive age. The normal MR spectroscopy data reported here will help to determine whether brain metabolism is altered, especially when subtle anatomic changes are observed on conventional images. Some examples of impaired fetal brain development studied by MRS are illustrated.
    Mots-clés : aging, Aspartic Acid, Brain, Choline, Creatine, crmbm, Female, Fetal Development, Fetus, gamma-Aminobutyric Acid, Humans, Inositol, Linear Models, Magnetic Resonance Spectroscopy, Taurine.

  • Girard, N, Gouny, SC, Viola, A, Le Fur, Y, Viout, P, Chaumoitre, K, D'Ercole, C, Gire, C, Figarella-Branger, D & Cozzone, PJ 2006, “Assessment of normal fetal brain maturation in utero by proton magnetic resonance spectroscopy”, Magnetic resonance in medicine: official journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine, vol. 56, no. 4, p. 768-775.
    Résumé : Cerebral maturation in the normal human fetal brain was investigated by in utero localized proton MR spectroscopy ((1)H MRS). Fifty-eight subjects at 22-39 weeks of gestational age (GA) were explored. A combination of anterior body phased-array coils (four elements) and posterior spinal coils (two to three elements) was used. Four sequences were performed (point-resolved spectroscopy (PRESS) sequence with short and long TEs (30 and 135 ms), with and without water saturation). A significant reduction in myo-inositol (myo-Ins) and choline (Cho) levels, and an increase in N-acetylaspartate (NAA) and creatine (Cr) content were observed with progressing age. A new finding is the detection of NAA as early as 22 weeks of GA. This result is probably related to the fact that oligodendrocytes (whether mature or not) express NAA, as demonstrated by in vitro studies. Cho and myo-inositol were the predominant resonances from 22 to 30 weeks and decreased gradually, probably reflecting the variations in substrate needed for membrane synthesis and myelination. The normal MRS data for the second trimester of gestation (when fetal MRI is usually performed) reported here can help determine whether brain metabolism is altered or not, especially when subtle anatomic changes are observed on conventional images.
    Mots-clés : aging, Algorithms, Aspartic Acid, Brain, Brain Chemistry, crmbm, Female, Fetal Development, Gestational Age, Humans, Linear Models, Magnetic Resonance Spectroscopy, Pregnancy.


Journal Article

  • Fogliarini, C, Chaumoitre, K, Chapon, F, Fernandez, C, Lévrier, O, Figarella-Branger, D & Girard, N 2005, “Assessment of cortical maturation with prenatal MRI: part II: abnormalities of cortical maturation”, European Radiology, vol. 15, no. 9, p. 1781-1789.
    Résumé : The fetal cortical maturation is a long process with predefined steps. Abnormalities can occur at different stages of cortical maturation, resulting in various malformations. They can result from disturbance in cell proliferation, cell differentiation, cell migration and in organization of the cortex. Analysis of the different abnormalities of cortical maturation is given with illustrations of the principal malformations encountered in utero and accessible to MRI.
    Mots-clés : Cerebral Cortex, Fetal Development, Fetus, Humans, Magnetic Resonance Imaging, Prenatal Diagnosis.

  • Fogliarini, C, Chaumoitre, K, Chapon, F, Fernandez, C, Lévrier, O, Figarella-Branger, D & Girard, N 2005, “Assessment of cortical maturation with prenatal MRI. Part I: Normal cortical maturation”, European Radiology, vol. 15, no. 8, p. 1671-1685.
    Résumé : Cortical maturation, especially gyral formation, follows a temporospatial schedule and is a good marker of fetal maturation. Although ultrasonography is still the imaging method of choice to evaluate fetal anatomy, MRI has an increasingly important role in the detection of brain abnormalities, especially of cortical development. Knowledge of MRI techniques in utero with the advantages and disadvantages of some sequences is necessary, in order to try to optimize the different magnetic resonance sequences to be able to make an early diagnosis. The different steps of cortical maturation known from histology represent the background necessary for the understanding of maturation in order to be then able to evaluate brain maturation through neuroimaging. Illustrations of the normal cortical maturation are given for each step accessible to MRI for both the cerebral hemispheres and the posterior fossa.
    Mots-clés : Brain, Cerebral Cortex, Female, Fetal Development, Humans, Magnetic Resonance Imaging, Pregnancy, Prenatal Diagnosis.
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