[Subocclusive transvenous approach of dural arteriovenous fistula]. / Tratamento suboclusivo por via transvenosa de fístulas arteriovenosas durais.

INTRODUCTION: Dural arteriovenous fistulae (DAVF) are usually acquired and when presented with cortical venous drainage are associated with high risk of hemorrhage. They can be treated by arterial or venous embolization, by surgery or by the combination of both techniques. Transvenous approach induces venous sinus thrombosis increasing the risk of venous stroke and/or hemorrhage. OBJECTIVE: Review of all the cases of transvenous embolization of lateral sinus arteriovenous fistulas treated in our department. Our main objective is to evaluate the clinical/imaging results of this treatment and the second goal is to discuss possible advantages of the subocclusive approach in the first session of transvenous treatment. RESULTS: The authors present six clinical cases of DAVF with the following clinical symptoms: visual disturbances (3); ear pulsatile bruit (3); headaches (2); subarachnoid hemorrhage (1); subjective hearing loss (1); optic disc edema (1); hemiparesis (1). Angiographic classification was: Cognard IIa, (3), IIab (2) e IV (1), all of the lateral sinus. The main afferent branches arised from: ipsilateral ECA (6); ipsilateral ICA (6); ipsilateral VA (6); contralateral ECA (5); contralateral VA (5); contralateral ICA (3); ipsilateral PCA (1). Transarterial approach was the first approach in all patients with satisfactory but transient results. It was always followed by transvenous embolization of the lateral sinus with GDC coils. Subocclusive approach was achieved in five patients with the persistence of some afferent arteries. Follow-up angiography in four of them showed "spontaneous" thrombosis of the lateral sinus with clinical and angiographic cure. Thrombosis occurred once during the initial transvenous procedure. There were no complications or new neurological signs or symptoms in any patient. CONCLUSIONS: Transvenous treatment of DAVF has led to technical and clinical success without procedure complications. We think that subocclusive approach of the venous sinus with coils can cause less hemodynamic changes with a slower thrombosis rate and less complications, unchanging the angiographic and clinical resolution.

Task-specific contribution of the human striatum to perceptual-motor skill learning.

Acquisition of new perceptual-motor skills depends on multiple brain areas, including the striatum. However, the specific contribution of each structure to this type of learning is still poorly understood. Focusing on the striatum, we proposed (a) to replicate the finding of impaired rotary pursuit (RP) and preserved mirror tracing (MT) in Huntington's disease (HD); and (b) to further explore this putative learning dissociation with other human models of striatal dysfunction (i.e., Parkinson's disease and focal vascular damage) and two new paradigms (i.e., Geometric Figures, GF, and Control Stick, CS) of skill learning. Regardless of the etiology, participants with damage to the striatum showed impaired learning of visuomotor tracking skills (i.e., RP and GF), whereas the ability to learn skills that require motor adaptation (i.e., MT and CS) was not affected. These results suggest a task-specific involvement of the striatum in the early stages of skill learning.

Neonatal pyruvate dehydrogenase deficiency due to a R302H mutation in the PDHA1 gene: MRI findings.

Pyruvate dehydrogenase (PDH) deficiency is one of the most common causes of congenital lactic acidosis. Correlations between the genetic defect and neuroimaging findings are lacking. We present conventional and diffusion-weighted MRI findings in a 7-day-old male neonate with PDH deficiency due to a mosaicism for the R302H mutation in the PDHA1 gene. Corpus callosum dysgenesis, widespread increased diffusion in the white matter, and bilateral subependymal cysts were the main features. Although confirmation of PDH deficiency depends on specialized biochemical analyses, neonatal MRI plays a role in evaluating the pattern and extent of brain damage, and potentially in early diagnosis and clinical decision making.

[Neuro-Behçet: MR study of a group of patients]. / Neuro-Behçet: características imagiológicas.

Behçet's disease is a chronic inflammatory, multisystemic disease of unknown aetiology. Central nervous system involvement occurs in a variable proportion of cases (4 to 49%) and is due to intracranial hypertension secondary to dural sinus thrombosis, inflammatory parenquimal lesions or recurrent meningoencephalitis. We reviewed 12 patients, 7 men and 5 women, aged between 27 to 40 years at the time of diagnosis. Neurological manifestations were secondary to parenquimal lesions in 7 patients, meningoencephalitis in 3 patients (including one with extensive medullary lesion) and dural sinus thrombosis in 2. Magnetic Resonance (MR) findings in Neuro-Behçet are non-specific. Nevertheless, MR has a role in characterizing brain lesions topography, helping in the diagnosis and in the follow-up of these patients.

[Merosin-positive congenital muscular dystrophy, white matter abnormalities, and bilateral posterior occipital cortical dysplasia]. / Distrofia muscular congénita merosina positiva, anormalidades da substância branca e displasia cortical occipital posterior bilateral.

Congenital muscular dystrophy (CMD) is one of the most frequent dystrophies of childhood, which is commonly characterized by neonatal muscle impairment with or without clinical evidence of central nervous system involvement. CMDs were classified into five clinically distinct forms: the two classical CMDs with and without deficit of the a2 laminin chain (merosin) caused by mutations on chromosome 6q2, the Fukuyama CMD (severe form, initially described in Japanese patients and recently linked to the chromosome 9q31-33), Walker-Warburg syndrome and the muscle-eye-brain disease described in Finnish patients. The majority of these forms have severe clinical and imagiological involvement of SNC. This aspect is rarely observed on classical CMD, particularly in the merosin-positive form. We describe a case of a 28 year-old woman, with clinical and histopathological signs of classical CMD merosin-positive (no deficient), without mental retardation, but with epilepsy. MRI T2 weighted images, revealed diffuse and symetrical high signal white matter of both cerebral hemispheres, affecting corpos calosum, posterior arms of internal capsules and the piramidal tract to mesencephalon. It also disclosed diffuse and symetrical high signal of basal ganglia, specially, the head of caudate nuclei. These were associated with bilateral occipital posterior cortical dysplasia. The observed imagiological pattern could represent a new subtype of CMD, hybrid between classical CMD and the severe forms, however it is not clear where it fits in the spectrum. This case denotes the possible envolvement of SNC in patients merosin-positives. Based on this findings we suggest doing MRI scans to all patients with CMD no deficient in merosin.

[Aneurysmal malformation of the vein of Galen in adults]. / Malformação aneurismática da veia de galeno no adulto.

We present an adult male harbouring a vascular malformation, manifested by haemorrhage, which localization, arterial feeders and venous drainage, match the pattern of choroidal type vein of Galen aneurysmal malformations seen in babies, excepting the absence of anterior choroidal arteries participation. A few cases of vein of Galen aneurysmal malformations were already reported in adults, but haemorrhage was never well documented. This haemorrhage may have a pathogenesis similar to those of pial arteriovenous malformations.

[Choroidal type aneurysmal malformation of the vein of Galen associated with Dandy-Walker malformation in an adult]. / Malformação aneurismática da veia de Galeno do tipo coroidal num adulto associada a malformação de Dandy-Walker.

Lasjaunias differentiated true vein of Galen aneurysmal malformations (MAVG), which drain to the median prosencephalic vein of Markowski, the embryonic precursor of the vein of Galen, from the aneurysmal dilatations of vein of Galen (VGDA), which reveal venous drainage into a dilated vein of Galen, but already formed. In angioarchitectural terms, MAVG can still be divided in two subtypes: the mural form and the choroidal form, the most common. The authors describe the clinical case of a 18 years-old female, without symptoms until July 2001, who presented an episode of impaired equilibrium associated with vomits and non-specific vision disturbances. This episode had an approximate duration of 6-8 hours with complete recovery. Neuroimaging studies were performed including CT, MRI and digital angiography, disclosed an aneurysmal vein of Galen malformation of choroidal type and Dandy-Walker malformation, association that the authors couldn't found so far described in the literature.