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.

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.