Biomedical subjects

Jacqueline Delavelle

Publications and source records attributed to Jacqueline Delavelle.

13 recordsLinked to original sources

PubMed2006

Abnormal patterns of cortical gyrification in velo-cardio-facial syndrome (deletion 22q11.2): an MRI study.

Velo-cardio-facial syndrome (VCFS), also known as 22q11.2 deletion syndrome, is a common genetic condition associated with increased risk for developing schizophrenia. Given that cortical malformations play an integral role in the pattern of neuroanatomical alterations associated with VCFS, the aim of the present study was to quantify and localize gyral abnormalities. Magnetic resonance images were obtained on a 1.5 T scanner. The gyrification index (GI), a measure of the degree of cortical complexity, was differentially calculated for each lobe using a semi-automated protocol. The GI was calculated for 37 patients affected by VCFS as well as for 36 comparison individuals group-matched for age, handedness, and gender. The subjects affected by VCFS showed a significant decrease in the GI in the frontal and parietal lobes compared with the control group. The pattern of decreased gyrification in the frontal and parietal lobes further defines the structural changes associated with the syndrome and suggests underlying abnormalities in neural connectivity. Aberrant connectivity may be partially responsible for the cognitive and behavioral impairments in the syndrome, as well as the high incidence of schizophrenia among affected individuals.

Adolescent↗

PubMed2005

Reversible cytotoxic edema in the splenium of the corpus callosum related to antiepileptic treatment: report of two cases and literature review.

PURPOSE: Clinically silent lesions localized in the splenium of the corpus callosum (SCC) are a rare finding in the magnetic resonance imaging (MRI) of patients receiving antiepileptic drugs (AEDs). They are usually of benign character but may induce unnecessary complementary examinations if their nature is unrecognized. So far, 22 cases have been described in the literature, for which different etiologies have been proposed. We describe two further cases and discuss the probable lesion etiology. METHODS: We report two cases including a 25-year-old male patient and a 12-year-old female patient with a transient SCC lesion discovered in the context of a presurgical epilepsy evaluation. RESULTS: Comprehensive MRIs, including diffusion tensor imaging-based fiber tracking of the lesion, revealed a cytotoxic edema not disrupting neuronal fibers. Serum arginine vasopressin (AVP) measurements revealed an altered secretion during the acute phase in one patient. CONCLUSIONS: On the basis of our results, we hypothesize that the lesion consists of a cytotoxic edema, possibly induced by abrupt AED concentration changes and associated to alterations of AVP secretion.

Adolescent↗

PubMed2005

Subcortical nuclei volumetry in idiopathic generalized epilepsy.

PURPOSE: The exact anatomic and neurophysiologic correlates of idiopathic generalized epilepsy (IGE) in humans are still not well understood, although the thalamus has frequently been invoked as the crucial structure in the generation of primary generalized seizures. The few in vivo magnetic resonance (MR)-based studies in IGE patients suggest an altered cortical/subcortical gray matter ratio, but with no evidence of structural alterations of the thalamus. In this study, we sought to determine the volumes of the other subcortical structures. METHODS: The volumes of the caudate nucleus, putamen, pallidum as well as the thalamus were each determined in both hemispheres in 11 patients with various IGE syndromes, normalized for whole-brain volumes and then compared with 15 age-matched controls. RESULTS: No differences were noted in thalamic volumes, confirming previous reports. However, smaller subcortical volumes were noted in the IGE patients (p < 0.009), mainly due to smaller putamen bilaterally (p < or = 0.015). CONCLUSIONS: It is speculated that the presence of discrete frontal dysfunction, as noted in neuropsychological studies in IGE patients, indirectly supports our results because the putamen projects predominantly to the frontal cortex. Larger studies with more homogeneous patient populations are needed to determine the robustness of these findings and whether they are specific for particular IGE syndromes.

Adult↗

PubMed2005

Arterialization of cerebral veins on dynamic MDCT angiography: a possible sign of a dural arteriovenous fistula.

OBJECTIVE: MDCT angiography allows fast imaging of the cerebral vessels, and its potential as a noninvasive technique to detect vascular abnormalities on the basis of morphologic changes is well established. We analyzed vascular enhancement patterns of cerebral venous structures on MDCT angiography, which enabled us to diagnose dural arteriovenous fistula. CONCLUSION: MDCT angiography performed during an early arterial phase showed asymmetrically higher contrast intensity in the transverse or sigmoid sinus, or both, in five patients. In all patients, digital subtraction angiography confirmed the presence of a dural arteriovenous fistula on the side on which the higher contrast intensity appeared. Radiologists should actively look for this sign in the imaging workup of patients presenting with nonspecific symptoms that might be related to a dural arteriovenous fistula.

Aged↗

PubMed2004

Occipital extra- and intracranial lipoencephalocele associated with tectocerebellar dysraphia.

OBJECTS: Tectocerebellar dysraphism was first described by Padget and Lindenberg, together with occipital encephaloceles, cerebellar midline defects, tectal beaking, posterior kinked and displaced brainstem, and inverted cerebellum. We present a unique case of lipoencephalocele associated with tectocerebellar dysraphia and discuss the etiologies of both pathologies. The importance of the developmental comprehension of posterior fossa malformations is stressed. CASE REPORT: A 9-month-old girl in good health was referred for a huge occipital mass. On local examination, the patient had a rounded mass about 10 x 12 cm in size, covered by alopecic skin, with a small eccentric dimple without any discharge. Magnetic resonance imaging revealed a lipoencephalocele with an intra- and an extracranial part, associated with tectocerebellar dysraphia with no aspect of inverted cerebellum as originally described in the tectocerebellar dysraphia. Resection of the extracranial part of the lipoma was performed for esthetic reasons. The intracranial part remained in situ. CONCLUSION: The association of lipoencephalocele and tectocerebellar dysraphia is extremely rare. The functional prognosis seems to be less severe for this combination than for the isolated tectocerebellar dysraphia. This association favors the dysraphic theory for the embryogenesis of the lipoma. It seems safe to restrict the surgery of this bizarre malformation to its external part.

Cerebellum↗

PubMed2004

Combination of event-related fMRI and diffusion tensor imaging in an infant with perinatal stroke.

Focal ischemic brain injury, or stroke, is an important cause of later handicap in children. Early assessment of structure-function relationships after such injury will provide insight into clinico-anatomic correlation and potentially guide early intervention strategies. We used combined functional MRI (fMRI) with diffusion tensor imaging (DTI) in a 3-month-old infant to explore the structure-function relationship after unilateral perinatal stroke that involved the visual pathways. With visual stimuli, fMRI showed a negative BOLD activation in the visual cortex of the intact right hemisphere, principally in the anterior part, and no activation in the injured hemisphere. The functional activation in the intact hemisphere correlated clearly with the fiber tract of the optic radiation visualized with DTI. DTI confirmed the absence of the optic radiation in the damaged left hemisphere. In addition, event-related fMRI (ER-fMRI) experiments were performed to define the characteristics of the BOLD response. The shape is that of an inverted gamma function (similar to a negative mirror image of the known positive adult BOLD response). The maximum decrease was reached at 5-7 s with signal changes of -1.7 +/- 0.4%.Thus, this report describes for the first time the combined use of DTI and event-related fMRI in an infant and provides insight into the localization of the fMRI visual response in the young infant and the characteristics of the BOLD response.

Asphyxia Neonatorum↗

PubMed2004

February 2004: a 44-year-old man with a 2-year history of epistaxis.

A 44-year old man presented with a 2-year history of epistaxis and a nodular lesion in the nasopharyngeal mucosa. Neuroimaging revealed a midline nasopharyngeal tumor extending through the skull base to the clivus. Following surgical resection, histological studies showed a paraganglioma, a tumor with a typical nesting pattern, abundant capillary network, and strong immunoreactivity for neuroendocrine markers. Paragangliomas of the head and neck are rare tumors, which may come to the neuropathologist's attention because of their propensity for intracranial spread. In particular, paragangliomas located in the nasopharynx may generate diagnostic difficulties, as they appear to have no connection with major paraganglia in the region. Morphologic criteria do not allow distinguishing between benign and malignant forms.

Adult↗

PubMed2003

Chronic parkinsonism associated with cirrhosis: a distinct subset of acquired hepatocerebral degeneration.

CONTEXT: The clinical, neuroradiological, and biological characteristics of the so-called acquired hepatocerebral degeneration have not yet been fully determined and its frequency remains largely uncertain. OBJECTIVES: To prospectively study the prevalence of extrapyramidal symptoms in patients with moderate to severe cirrhosis of various causes, to delineate the main neurological features of the condition, and to establish correlations with neuroradiological and biological findings. PATIENTS AND METHODS: During a 1-year period, all consecutive patients with cirrhosis who were potential candidates for liver transplantation were screened for extrapyramidal features. When extrapyramidal features were present, further workup included a detailed neurological examination, magnetic resonance imaging of the brain, a comprehensive battery of neuropsychological tests, extensive blood tests, and, in some cases, cerebrospinal fluid analysis. SETTING: A community-based hospital. RESULTS: From 51 patients screened, 11 (21.6%) exhibited moderate to severe parkinsonism sometimes associated with focal dystonia. Typical features included rapid progression over months, symmetric akinetic-rigid syndrome, postural but not resting tremor, and early postural and gait impairment. Neuropsychiatric manifestations were minimal. Some patients were responsive to levodopa therapy. In all patients, magnetic resonance imaging scans showed striking hyperintensities on T1-weighted images typically involving the substantia nigra and the globus pallidus bilaterally. Whole blood and cerebrospinal fluid manganese concentrations were severalfold above the reference range. CONCLUSIONS: Cirrhosis-related parkinsonism may represent a unique, consistent, and common subset of acquired hepatocerebral degeneration, whose features are permanent and entirely different from acute hepatic encephalopathy episodes. This form of parkinsonism can be clearly distinguished from other forms of parkinsonism of middle to advanced age, based on a suggestive association of clinical, neuroradiological, and biological abnormalities. Our findings support the concept of the toxic effects of manganese being the major determinant of basal ganglia dysfunction leading to the predominantly extrapyramidal central nervous system manifestations of cirrhosis observed in these patients.

Aged↗

PubMed2003

[Cerebral sinus thrombosis in Behçet disease: case report and review of the literature].

BACKGROUND: Behçet's disease is a chronic inflammatory disorder, clinically characterised by multisystemic vasculitis. Primary neurologic involvement in childhood is quite exceptional. We report a case of a child with recurrent venous thrombosis of the dural sinus. Behçet's disease was diagnosed. HISTORY AND SIGNS: A 13-year-old boy from Eritrea was referred to our clinic with severe headaches and photophobia one month after onset. Ophthalmological examination disclosed a bilateral papilledema. Recurrent oral ulcers and pseudo-folliculitis were present. Pathergy test was positive. THERAPY AND OUTCOME: Complementary investigations disclosed an inflammatory syndrome. Computertomography was normal. Cranial magnetic resonance venography disclosed multiple cerebral sinus thrombosis (superior sagittal sinus, sigmoid sinus and lateral left sinus). There was no evidence of infectious, inflammatory or hypercoagulation disorder. A Behçet's disease was diagnosed based on the medical history and clinical examination. Whilst his general health deteriorated rapidly before treatment, he improved quickly after the onset of therapy with immunosuppression (Prednisone and Ciclosporine) in combination with anticoagulation (coumarin/Sintrom). CONCLUSION: Behçet's disease is uncommon and difficult to diagnose in children. Neurologic involvement as a first presentation is rarely described, but might be underestimated. We emphasise, therefore, the systematic application of magnetic resonance venography in children with unclear persistent headaches.

Adolescent↗

PubMed2003

[New brain imaging techniques].

Neuroimaging technologies have improved neurology and neurosurgery by providing tools to look inside the brain and investigate its functions and diseases. As for any tool, the users should know the basics of each technique and be aware about their uses and limitations. Here we review these new techniques and illustrate their use with examples from studies at the University Hospital in Geneva. From all the techniques, MRI (Magnetic Resonance Imagery) has the highest spatial resolution. Taking advantage of the magnetic properties of the hydrogen nucleus, it is possible to reach a sub-millimeter resolution in 3D. When MRI images are digitized, they can be treated to perform re-slicing, segmentation and 3D reconstruction of cortical surfaces, as well as to measure anatomical structures (volumetry). Functional MRI (fMRI) is based on blood oxygenation changes when a task is performed or when epileptic activity occurred. Then it can be used to non-invasively show for example language, motor or epileptic network activation. Electromagnetic imaging techniques, based on EEG and MEG, have the power to localize in 3D the electrical activity of the brain with millisecond temporal resolution and then to follow the temporal activation of neuronal networks. These techniques use mathematical models and algorithms to compute 3D tomography from 2D recordings on the scalp. In the case of epilepsy, EEG allows epileptic foci identification among propagation sites when it is recorded with a sufficient number of electrodes (> 100) and when realistic head models are used. The functional imaging techniques from nuclear medicine (PET and SPECT) have become very useful in neuroscience to explore cerebral changes associated with neuronal pathologies as well as cognitive and sensory tasks. Many efforts have been made to develop new cameras and models to increase the range of research and clinical applications. Co-registration of structural and functional images allows us to add functional information to a structural deficit, or conversely to better interpret functional images such as PET, SPECT and EEG in terms of specific anatomy. In the case of SPECT and fMRI, substraction between ictal and interictal exams points out areas involved in epileptic processes.

Brain Diseases↗

PubMed2002

Early onset and rapidly progressive subacute sclerosing panencephalitis after congenital measles infection.

UNLABELLED: We report an 18-month-old girl with rapidly progressive subacute sclerosing panencephalitis, whose non immunised mother had measles at the time of delivery. The patient presented with repetitive episodes of myoclonic jerks of the head and arms, followed by a drop of head and trunk with frequent falls. EEG, CSF studies and MRI confirmed the diagnosis. Despite therapy with isoprinosine and valproate, seizure activity continued and she became vegetative within 2 months, with severe spasticity and swallowing difficulties, and died at the age of 28 months. Early age of onset and rapid progression were most likely related to haematogenous in utero acquisition of the measles virus prior to delivery, as well as immaturity of neuronal and immune systems. CONCLUSION: this case emphasises the importance of a high measles vaccine coverage in the population in order to prevent the risk of disease in general and, in particular, gestational measles.

Age of Onset↗

PubMed2002

Persistence of mild parkinsonism 4 months after liver transplantation in patients with preoperative minimal hepatic encephalopathy: a study on neuroradiological and blood manganese changes.

Pallidal hyperintensity at magnetic resonance imaging (MRI) correlates to blood manganese (Mn) levels and parkinsonian signs in patients with cirrhosis. Similarly, metabolite changes in the basal ganglia (BG) at proton spectroscopy are related to these neurological signs. The evolution of these abnormalities after liver transplantation (OLT) is incompletely described. We evaluated 14 unselected consecutive patients with cirrhosis (minimal hepatic encephalopathy [HE] n=8, no HE n=6) before and 4 months after successful OLT for the evolution of parkinsonism using a validated scale (the United Parkinson's Disease Rating Scale, or UPDRS). Pallidal intensity at MRI, spectroscopic changes in the BG at magnetic resonance spectroscopy (MRS), and whole blood manganese concentrations were measured. After OLT in patients with preoperative minimal HE, the UPDRS scores improved, but mild parkinsonism persisted (16.1+/-3.6 to 6.2+/-4.8, P<0.05). Pallidal hyperintensity remained abnormal in 5/8 of cases, but spectroscopic changes normalized in all patients. Blood Mn remained elevated in 4/6 patients. In patients without HE, UPDRS values remained negligible (2.42+/-1.5 to 2.5+/-1.4). Pallidal hyperintensity normalized in 7/8 patients and spectroscopic changes normalized in all patients. Blood Mn remained elevated in 5/6 patients. Four months after successful OLT, patients with preoperative minimal HE and severe pallidal hyperintensity showed persistent mild parkinsonism. The role of blood manganese determination appears limited in the monitoring of MRI and parkinsonian signs changes after OLT.

Adult↗

PubMed2002

The craniocervical venous system in relation to cerebral venous drainage.

BACKGROUND AND PURPOSE: Passing from the supine to the upright position favors cerebral venous outflow into vertebral venous systems rather than into the internal jugular veins. We sought to determine venous connections between dural venous sinuses of the posterior cranial fossa and craniocervical vertebral venous systems. METHODS: Corrosion casts of the cranial and cervical venous system were obtained from 12 fresh human cadavers, and anatomic confirmation was made by dissection of three previously injected fresh human specimens. MR venography was performed to provide radiologic correlation. RESULTS: The lateral, posterior, and anterior condylar veins and the mastoid and occipital emissary veins were found to represent the venous connections between the dural venous sinuses of the posterior cranial fossa and the vertebral venous systems. This study revealed the nearly constant presence of the anterior condylar confluent (ACC) located on the external orifice of the canal of the hypoglossal nerve. The ACC offered multiple connections with the dural venous sinuses of the posterior cranial fossa, the internal jugular vein, and the vertebral venous system. All these structures were shown by MR venography. CONCLUSION: The lateral, posterior, and anterior condylar veins and the mastoid and occipital emissary veins connect the dural venous sinuses of the posterior cranial fossa with the vertebral venous systems. These connections are clinically relevant, because encephalic drainage occurs preferentially through the vertebral venous system in the upright position. The ACC is a constant anatomic structure that may play an important role in the redirection of cerebral blood in the craniocervical region.

Aged↗