Preoperative assessment of stenosis of the epiaortic vessels: can colour-Doppler ultrasound really supplant angiography?

PURPOSE: To evaluate the diagnostic role of digital angiography compared with colour-Doppler US in the study of epiaortic vessel stenoses and the degree of morbidity associated with angiography. MATERIALS AND METHODS: Out of 2,000 angiographic examinations of the epiaortic vessels performed for the concurrent presence of clinical findings of cerebrovascular insufficiency and colour-Doppler US findings of carotid-vertebral stenosis, a randomized sample of 200 patients was evaluated. The retrospective review of medical records provided the surgical data of the stenosis which were subsequently compared with the angiography and colour-Doppler US findings, and with the clinical and laboratory data to identify the possible complications of angiography. RESULTS: Diagnostic agreement was 75%. Colour-Doppler US underestimated stenosis in 16.5% and overestimated stenosis in 8% of cases. In 18% of cases there was a diagnostic gain of angiography (vascular lesions associated with main lesion), which also provided clinically important incidental findings (intracranial aneurysms, meningiomas) in 6.5% of patients. No relevant complications resulting from the angiographic procedure were recorded. CONCLUSIONS: Angiography allowed a more accurate evaluation of the degree of stenosis compared with colour-Doppler ultrasound. Moreover, it allowed diagnosis of important associated conditions that may affect therapeutic planning. In our series, we recorded no important complications related to angiography. Therefore, angiography remains the standard of reference in the preoperative evaluation of patients with clinically diagnosed cerebral ischaemia. Though fairly reliable as a first-line investigation, Colour-Doppler US is not sufficiently exhaustive as a pre-operative evaluation tool.

Endovascular treatment of intracranial arterio-venous malformations with Onyx embolization: preliminary experience.

PURPOSE: Intracranial arterio-venous malformations (AVM) often represent a complex clinical problem as regards indications to treatment, the choice of treatment and the technical difficulties related to treatment. In the last twenty years, endovascular treatment of intracranial arterio-venous malformations was primarily based on an acrylic glue (Hystoacril) whose endovascular use is not free from risks. A new product for endovascular embolization, named ONYX, has been recently been made commercially available. It is a bio-compatible liquid polymer that precipitates and solidifies in contact with blood, thus forming a soft and spongy embolus. The aim of this study was to evaluate our preliminary results in the endovascular embolization of intracranial AVM with Onyx. MATERIALS AND METHODS: Ten patients were treated (7 men, 3 women; mean age: 29 years, range: 12-48 years) for a total of 37 embolizations, 22 with Onyx and 15 with acrylic resin. RESULTS: Nidus occlusion was complete in 2 cases, >90% in 2 cases, >50 and <90% in 3 cases and <50% in the remaining 3 cases. The following complications were recorded: two transient and one mild permanent neurological deficits, two clinically silent cases of moderate subarachnoid haemorrhage, four catheters glued to the injection site, three cases of treatment discontinuation due to continuous and massive reflux of Onyx into the afferent artery peduncle. CONCLUSIONS: This early experience showed that while Onyx has good embolization potential it also presents some disadvantages, which need to be overcome before this product can be considered easy and safe to use on a large scale.