Interventional Neuroradiology

Flow studies are important to understanding pathogenesis and treatment of cerebral aneurysms, but have not been possible in the clinical setting. We used experimental aneurysms established in and then removed from pigs to compare and correlate flow studies by high-speed video photography of introduced particles and by clinically applicable digital subtraction angiography.

Venous pouches were used to create aneurysms in incised common carotid arteries. After aneurysms and parent arteries were removed, specimens were rendered translucent with solvents so they could be studied by video photography of introduced plastic particles in addition to digital subtraction angiography with iodinated contrast material. Regions of interest were studied individually.

Mean transit time for contrast in the preparation correlated with videographically measured particle flow velocity (r = 0.616).

Digital subtraction angiography should be useful in evaluation of flow in the clinical assessment and treatment of cerebral aneurysms, such as in endovascular therapy.

There are few experimental models of arteriovenous malformations (AVM). The following study was designed to evaluate an easy-to-perform method in a canine model.

Bilateral high-flow carotid to external jugular vein arteriovenous fistulae (AVF) were created in three adult dogs. 21 days after surgery one AVF was occluded by a coated stent, whereas the contralateral side remained patent. Frequent angiograms of the carotid and the vertebral arteries were performed in the nine months after surgery to investigate the effects of long-standing high-flow AVF.

Because of a significant steal effect, the fistulae recruited arterial blood flow at a rapid rate from the ipsilateral vertebral artery and to lesser extent from the contralateral side, which was only disclosed after occlusion of the contralateral AVF. These cephalic pseudo AVMs were seen in all three dogs.

The model presented is easy to establish and shows angioma-like morphological components comparable to human AVM. It is useful for the testing of new catheters and embolic materials as well as in the training of superselective navigation with microcatheters. However, it is unsuitable for examination of intracranial pathophysiology.

Spontaneous vertebrovertebral arteriovenous fistula (SWAVF) is a rare condition which often presents as a bruit. We reviewed the clinical and imaging records of 12 patients with 13 SVVAVF fistulae who were managed at our institution over the last 14 years. Two patients had predisposing conditions, neurofibromatosis in one and Ehlers-Danlos syndrome in the other. Nine of the patients presented with a bruit; one patient presented with a myelopathy and one with congestive cardiac failure. Six of the 13 fistulae were at C1 and five of these six were children. In seven of the fistulae there was retrograde flow in the distal vertebral artery. Eight patients underwent endovascular treatment. Six required both contralateral and ipsilateral vertebral artery approaches. Coils (two patients), balloons (three patients), or a combination of agents including liquid adhesives (three patients) were used. Preservation of the vertebral artery was possible in three of the eight patients. Angiographic obliteration was obtained in all eight patients. There were no significant procedure-related complications. Embolisation is the primary treatment of SVVAVF and can be performed successfully with low morbidity. Preservation of the vertebral artery, although desired, is often not possible.

There are two important pathological features associated with carotid-cavernous fistula (CCF): the retrograde cortical venous drainage that can cause intracranial haemorrhage and non haemorrhagic neurological deficit and the retrograde ophthalmic venous drainage that causes orbital venous congestion and visual impairment.

We propose a sequential embolisation strategy by the selective occlusion of these two pathological features as the initial steps followed by occlusion of the rest of the cavernous sinus. Eight patients with spontaneous CCF were treated by transvenous embolisation using our embolisation strategy. The clinical features, angiographic findings, embolisation procedures, and clinical and angiographic outcomes were analyzed. The follow-up period ranged from one to 21 months. Clinical cure was achieved in six patients at one to two month follow-ups.

One patient with bilateral CCFs had clinical cure of the right eye and clinical improvement of the left eye at three-month follow-up. Another patient had clinical cure at one-month follow-up except residual VI nerve palsy. Two patients had complete angiographic obliteration of the fistula immediately after the embolisation procedure. Another three patients underwent follow-up angiography at one to 16 months and all showed angiographic cure. There were no immediate or late complications. Our embolisation strategy offers a safe and effective option in the embolisation of spontaneous CCF as demonstrated by the clinical results of our eight patients.

We report five cases of arteriovenous fistulae (AVFs) of the carotid system. Two were traumatic non penetrating injuries and involved the subarachnoid, extracavernous part of the intracranial internal carotid artery; two were spontaneous and involved the internal carotid artery in its extracranial portion; one was a spontaneous AVF of the ascending pharyngeal artery.

All the symptoms due to these AVFs were not related to the location of the fistula, but to the congestive venous drainage.

The revealing symptoms regressed and/or improved after transarterial detachable balloon embolisation that led to complete occlusion of the AVFs.

We describe a clinical case of the combined application of endovascular stent placement and GDCoils packing in the management of a ruptured wide necked intracranial aneurysm.

A 27-year-old man had a subarachnoid haemorrhage secondary to the rupture of a large wide necked left vertebral aneurysm. This aneurysm was judged to be inoperable. A functional occlusion test failed because of poor collateral flow and combined stenting and coiling was used to occlude the aneurysm with preservation of the parent artery.

A femoral approach was used. An 18 mm long ACS® Duet stent was placed across the base of aneurysm and expanded to 4mm to act as a buttress. A microcatheter was then advanced through the stent mesh and GDC's were deposited for occlusion.

This technique provides new possibilities for wide-necked intracranial aneurysms. Further studies are required on the mechanical and thrombogenic properties of stents and on the long-term follow-up, but this technology may play a role in some cases of aneurysm treatment.

Endovascular treatment of high flow arteriovenous fistula following a stab wound injury in a 25 year old man is reported. Previously performed proximal embolisation and surgical ligation failed to occlude the fistula but resulted in changes to the normal vascular anatomy and significant clinical and cosmetic disturbances.

A direct puncture of the draining vein was performed and the fistulous connection occluded by placement of detachable coils and deposition of glue.

Follow-up showed disappearance of the AVF as well as complete clinical recovery.

Histologic findings after Guglielmi detachable coils endovascular embolisation have been studied in experimental aneurysms. Few reports describe histopathologic reactions to platinum coils in humans. In this report we describe gross, light microscopic pathology and scanning electron microscopy study of a ruptured basilar tip artery aneurysm in a patient who died 16 hours following coiling.

One of the rare anomalies of the common carotid artery is the separate origin of the internal and external carotid artery. We present the case of a patient who was admitted to hospital for cerebral angiography to exclude an intracranial aneurysm.

The DSA revealed a giant aneurysm of the right internal carotid artery and separate origins of external and internal carotid arteries from the aortic arch. To our best knowledge no similar case has previously been reported.