A case of spontaneous brain arteriovenous malformation occlusion: Imaging analysis and clinical debate.

The spontaneous occlusion of brain arteriovenous malformations (bAVMs) is a rare event, particularly for unruptured ones. Associated factors include single-venous drainage and small nidus size. Most of the previously reported cases were ruptured bAVMs. We report the case of a middle-aged male patient with an unruptured, rolandic, left-sided bAVM associated with a 30-year history of refractory epilepsy. We documented the spontaneous thrombosis of the venous drainage of the AVM without any sign of bleeding. Finally, we underline the difference between ruptured-induced occlusion and truly spontaneous thrombosis of the bAVMs.

Intradural spinal cord arteriovenous shunts in a personal series of 210 patients: novel classification with emphasis on anatomical disposition and angioarchitectonic distribution, related to spinal cord histogenetic units.

OBJECTIVE: Few classifications of intradural spinal arteriovenous shunts (ID-SAVSs) have considered their anatomical localization in relation to their phenotype and angioarchitectonics. The authors propose another vision of ID-SAVSs allowing a reappraised classification based on analysis of the anatomical disposition, angioarchitecture, and histogenetic location of these vascular malformations. METHODS: The radiological and clinical records of 210 patients with ID-SAVSs were retrospectively reviewed, considering their localization, vascular architectonics, and correlation with the 5 histogenetic units of the spinal cord. Among these, 183 files with complete data allowed precise analysis of the ID-SAVSs. RESULTS: Among these 183 files (162 and 21 cases with single and multiple lesions, respectively), different entities were identified: 13 pial macro arteriovenous fistulas (MAVFs), 92 pial micro arteriovenous fistulas (mAVFs), 33 superficial pial niduses, and 69 intramedullary niduses. Thirteen sulcal shunts (either fistulas or niduses) were considered subtypes of pial lesions. Among the 21 multiple cases, 11 were monomyelomeric while 10 were multimyelomeric. Pial lesions, either fistulas or niduses, were dominantly vascularized by pial arteries (anterior or posterior depending on the localization of the shunt) and occasionally (except for MAVFs) by transmedullary arteries. Pial niduses occasionally extended into the funiculus by recruiting intrinsic veins or by extension of the nidus itself inside the white matter. Intramedullary niduses were always vascularized by both centrifugal and centripetal feeders, respectively, from sulcal arteries (SAs) and pial arteries. Sulcal lesions are pial lesions located within the ventral median sulcus and vascularized by SAs and veins. Single or multiple ID-SAVSs can be part of various syndromes such as hereditary hemorrhagic telangiectasia, Parkes-Weber, RASA1, CLOVES, and spinal arteriovenous metameric syndromes. Histogenetic analyses revealed a specific distribution of each ID-SAVS in the 5 histogenetic units of the spinal cord: intramedullary niduses were found almost equally from cervical to thoracic units, while MAVFs and mAVFs were mostly found from thoracic to postcrural ones. Pial niduses showed intermediate features between intramedullary and fistulous lesions and were mostly distributed from brachial to crural segments. CONCLUSIONS: Precise analysis of the anatomical disposition of ID-SAVSs in relation to functional histogenetic units allows a better understanding of these lesions and improved therapeutic management.

Primary conus medullaris arteriovenous shunt and secondary lumbo-sacral epidural arteriovenous fistula: One malformation can hide another.

We report an anatomical-based association between conus medullaris pial arteriovenous shunt that drain caudally towards the lumbosacral area with very delayed onset of an acquired lumbar epidural shunt, draining secondarily towards intradural veins and responsible for a venous congestive myelopathy with identical clinical symptoms. These patients require close clinical and imaging follow-ups in order to propose adequate treatments before onset of irreversible neurological deficits. MRA should include the lumbo-sacral area in its field of view.

Concomitant conus medullaris arteriovenous shunts and sacral dural arteriovenous fistulas: pathophysiological links related to the venous drainage of the lesions in a series of five cases.

BACKGROUND: Spinal cord arteriovenous shunts (scAVSs) are a group of lesions located in the spinal cord itself or in the surrounding structures. The most common scAVSs are spinal dural arteriovenous fistulas (sDAVFs), which are acquired lesions. The pathogenesis of sDAVFs involves thrombosis and venous hypertension as trigger factors. Intradural scAVSs such as spinal cord arteriovenous nidus type malformations (AVMs) and pial arteriovenous fistulas are less common than sDAVFs and are considered to have a so-called 'congenital' origin. The association between different concomitant scAVSs is very rare and the association of sDAVFs with intradural scAVSs has been described in only a few case reports. METHODS: We describe a case series of five patients presenting with a conus medullaris AVS associated with a lower lumbar or sacral DAVF. RESULTS: Three of our patients were <30 years old at presentation. In four of these five cases the intradural scAVS drained caudally, engorging the epidural plexus in the same location as the sDAVF. In only one case, who presented with thrombosis of the drainage of the main compartment of a conus medullaris pial AVF, was the location of the DAVF opposite to the location of the residual drainage. CONCLUSION: We discuss the pathophysiological link between scAVS and sDAVF on the basis of the rarity of the DAVF, the uncommon association between scAVS and sDAVF, the presence of sDAVF in young patients, and the venous hypertension created by the venous drainage towards the sacral area responsible for angiogenesis creating the dural shunt.

Spinal cord arteriovenous shunts of the ventral (anterior) sulcus: anatomical, clinical, and therapeutic considerations.

INTRODUCTION: Ventral sulcus spinal cord arteriovenous shunts (SCAVS) are rare vascular lesions that are located outside the spinal cord, are exclusively vascularized by the anterior spinal axis, and drain exclusively through the anterior spinal vein. We report the anatomical, clinical, and neuro-radiological features of SCAVS managed by our team. METHODS: We conducted a retrospective study of patients with SCAVSs evaluated by the senior author of this report (GR) between 1981 and 2014. Data were collected by reviewing clinical notes and by a systematic analysis of spinal angiograms and MRI. RESULTS: Among 358 patients, we identified 8 patients (3 women) with ventral sulcus spinal cord arteriovenous shunts. Mean age was 30.5 years. Six patients presented with progressive neurological symptoms, and two with acute neurological symptoms related to hematomyelia. Three shunts were located in the cervical cord, four in the thoracic cord, and one at the conus medullaris; there were two nidus type A-V shunts (AVMs) and six fistula type A-V shunts (AVFs). Seven patients were treated by endovascular therapy with glue embolization. Embolization led to anatomical cure in 5 cases, and a significant reduction of shunt volume and flow of more than 75% in 2 cases. In none of the cases we observed permanent morbidity. CONCLUSIONS: AVS of the ventral sulcus of the spinal cord are rare. Recognition of these lesions and precise localization of the anatomical space in which they are located, may allow a better understanding of their pathophysiology and clinical manifestations and guide proper therapeutic decisions.

MRI and MRA of spinal cord arteriovenous shunts.

The purpose of this review is to describe the diagnostic criteria for spinal cord arteriovenous shunts (SCAVSs) when using magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA), and to discuss the extent to which the different MRI and MRA sequences and technical parameters provide the information that is required to diagnose these lesions properly. SCAVSs are divided into four groups according to location (paraspinal, epidural, dural, or intradural) and type (fistula or nidus); each type of lesion is described. SCAVSs are responsible for neurological symptoms due to spinal cord or nerve root involvement. MRI is usually the first examination performed when a spinal cord lesion is suspected. Recognition of the image characteristics of vascular lesions is mandatory if useful sequences are to be performed-especially MRA sequences. Because the treatment of SCAVSs relies mainly on endovascular therapies, MRI and MRA help with the planning of the angiographic procedure. We explain the choice of MRA sequences and parameters, the advantages and pitfalls to be aware of in order to obtain the best visualization, and the analysis of each lesion.

Arteriovenous fistula of the filum terminale: radiological diagnosis and therapeutic management by embolization.

A 60-year-old man had progressive paraparesis, paresthesia of both lower limbs and sphincter dysfunction. He underwent MRI, which revealed perimedullar abnormal vascular channels associated with a hypersignal in the thoracolumbar cord. Because of the patient's age and symptomatology, a dural arteriovenous shunt was first suspected. MRA confirmed dilatation of the perimedullary venous channels, but also revealed an enlarged anterior spinal artery, a finding incompatible with a diagnosis of dural arteriovenous fistula. A lesion, vascularized by the anterior spinal axis and draining secondarily into the perimedullary veins, was thus suspected. Angiography diagnosed a microfistula of the filum terminale; selective distal catheterization of the arterial feeder from T11 to S1 was achieved, and the shunt closed by embolization with acrylic glue. The patient improved after endovascular treatment.

Developmental venous anomalies with capillary stain: a subgroup of symptomatic DVAs?

INTRODUCTION: Intracranial developmental venous anomalies (DVAs) are considered benign vascular dispositions; they are asymptomatic in the vast majority of cases. They represent extreme variations of the venous drainage and may rarely be responsible for focal venous ischemia leading to neurological dysfunction. The aim of the study is to analyze a group of patients with symptomatic DVAs with capillary stain at angiography. METHODS: We retrospectively reviewed the clinical and radiological features of patients in which a DVA was considered the cause of a neurological event. In all the patients, the DVA was suspected by angio-CT or MRI and conventional angiography was performed to detail the angioarchitecture of the DVA. RESULTS: A total of 7 patients and 11 DVAs were identified; three patients had multiple DVAs. Three DVAs were frontal, two were parietal, two were thalamic, one was in the midbrain, and three were cerebellar. Patients presented with progressive neurological deficits, seizures, or cerebral hemorrhage. All these DVAs were associated with a peculiar capillary stain at angiography. CONCLUSION: Although being normal anatomical variations, DVAs may create, because of hemodynamic unbalance, venous ischemia that induces angiogenic phenomena. MRI shows the suffering of the brain and angiography witnesses this angiogenesis under the form of capillary stain. Conventional angiography can thus provide useful information to recognize "atypical" symptomatic DVAs.

Partially thrombosed intracranial aneurysms: symptoms, evolution, and therapeutic management.

BACKGROUND: Partially thrombosed intracranial aneurysms (PTIAs) are different from saccular or nonthrombosed giant or large aneurysms, as they are characterized by multiple intramural thrombotic phenomena related to recurrent vessel wall dissections. METHODS: We retrospectively reviewed clinical and radiological files of 23 consecutive patients with PTIAs (mean age 49.3 years). Twenty-two lesions were studied by magnetic resonance imaging (MRI). Patients were managed by endovascular treatments, medically with steroids, or conservatively. RESULTS: Thirteen patients presented with progressive neurological symptoms. Subarachnoid hemorrhage was suspected but not proven in three. At MRI, 90.9% of PTIAs caused mass effect; perilesional T2 hypersignal compatible with edema was evident in 13.6%. Aneurysmal wall enhancement was detectable in 63.2% of the PTIAs and considered a marker of inflammatory processes. Parent artery occlusion was performed in seven patients with clinical improvement in six. Selective coiling was proposed in three patients (one improved, one remained stable, and one experienced symptoms progression). Three patients were treated with steroids and improved. Ten patients were managed conservatively: eight because spontaneous thrombosis of the lesion had been diagnosed and two because of clinical and radiological stability. CONCLUSIONS: The natural history of PTIAs is different from other aneurysms. They most commonly present with progressive neurological symptoms due to mass effect. MRI properly diagnoses PTIAs and allows precise follow-up, more accurately than angiography because it detects prominent "abluminal" features indicating inflammation and neovascularization. Spontaneous thrombosis is part of the natural history of PTIAs and it should be taken in consideration when discussing the therapeutic management.

Therapeutic management of intracranial dural arteriovenous shunts with leptomeningeal venous drainage: report of 53 consecutive patients with emphasis on transarterial embolization with acrylic glue.

OBJECT: There is a strong correlation between the venous drainage pattern of intracranial dural arteriovenous shunts (ICDAVSs) and the affected patients' clinical presentation. The ICDAVSs that have cortical venous reflux (CVR) (retrograde leptomeningeal drainage: Borden Type 2 and 3 lesions) are very aggressive and have a poor natural history. Although the necessity of treatment remains debatable in ICDAVSs that drain exclusively into a sinus (Borden Type 1), lesions with CVR must be treated because of the negative effects of the retrograde venous drainage. Surgery, radiosurgery, and embolization have been proposed for management of these lesions, but endovascular therapy is considered the most appropriate therapeutic strategy in ICDAVSs. New embolic materials, such as Onyx, have been recently developed and are considered to represent a kind of "gold standard" for embolization of these lesions. The purpose of this study is to emphasize the importance of transarterial embolization using acrylic glue in the therapeutic management of ICDAVSs with CVR, and to compare the results the authors obtained using this treatment with those reported in the literature for Onyx treatment of the same type of dural shunts. METHODS: The clinical and radiological records of 53 consecutive patients suffering from ICDAVSs with CVR (Borden Types 2 or 3) were reviewed. All cases were managed with the same angiographic and therapeutic protocol. Localization of the lesions, their clinical symptoms, their angioarchitecture, their therapeutic management, and the results were analyzed. RESULTS: Fourteen ICDAVSs were located at the superior sagittal sinus and/or convexity veins, 13 at the transverse and sigmoid sinuses, 10 at the tentorium, 5 in the anterior cranial fossa, 4 at the foramen magnum, 3 at the torcula, 2 at the straight sinus, and 1 at the vein of Galen. One patient presented with an infantile form of ICDAVS with multiple shunts. Hemorrhage had occurred in 36% of cases. Forty-three patients underwent transarterial embolization (42 with acrylic glue). Complete closure of the fistula was obtained in 34 patients. Suppression of the CVR with partial occlusion of the main shunt was achieved in all other cases. No mortality or permanent morbidity was observed in this series. CONCLUSIONS: Intracranial dural arteriovenous shunts can be safely managed by transarterial embolization, which can be considered in most instances as an effective first-intention treatment. Acrylic glue still allows a cheap, fast, and effective treatment with high rates of cures that compare favorably to those obtained with new embolic materials.