Interventional Neuroradiology

Hereditary haemorrhagic telangiectasia (HHT) is a heterogeneous disease that may present with different clinical phenotypes and different clinical expressions. Concerning the neurovascular expressions of this disease, the paediatric age group in particular presents with potentially devastating symptomatic phenotypes. The purpose of this article was to review the therapeutic results of endovascular treatment of neurovascular malformations in children.

A total of 31 children under the age of 16 were included in this retrospective analysis. All children were treated in a single centre. Twenty children presented with 28 arterio venous (AV) fistulae including seven children with spinal AV fistulae and 14 children with cerebral AV fistulae (one child had both a spinal and cerebral fistulae). Eleven children had small nidus type AV malformations. All embolizations were performed in a single centre employing superselective glue injection. Follow-up ranged between three and 168 months (mean: 66 months)

A total of 115 feeding vessels were embolized in 81 single sessions resulting in a mean overall occlusion rate of the malformation of 77.4% (ranging from 30 to 100%). Two of 30 patients (6.5%) died as a direct complication of the embolization procedure, two patients (6.5%) had a persistent new neurological deficit, eight patients (26.7%) were clinically unchanged following the procedure. In 11 patients (36.7%) an amelioration of symptoms but no cure could be achieved, six patients (20%) were completely asymptomatic following the endovascular procedure. In the surviving patients morphological complete occlusion was possible in twelve patients (38%), therapy is still not complete in six patients.

Since the natural history of neurovascular manifestations of HHT in children is associated with a high morbidity and mortality, therapeutic intervention is mandatory. In most instances a morphological target can be identified, therefore even partial and staged treatment can be performed. Our results demonstrate that in 27/31 patients these targeted interventions resulted in stabilizing the disease, ameliorating the symptoms or even in curing the patient. The endovascular approach employing glue as the embolizing agent represents therefore a safe and efficient way to control the neurovascular phenotypes of HHT.

The purpose of our study was to analyze the outcome of symptomatic radionecrosis following stereotactic radiosurgery for brain arterio venous malformations. Of 225 patients treated by linear accelerator radiosurgery for brain AVM, 16 (7, 1%) presented post-radiosurgery symptomatic radionecrosis on a mean follow-up period of 50 months (range 1–123 months). Once diagnosed with radionecrosis, 14 of 16 patients were subjected to high dose corticotherapy consisting of escalating doses of dexamethasone for several weeks. The mean interval of occurrence of new symptoms was 11.6 months post-radiosurgery (range 6–20 months). The mean time of follow-up was 2.9 years post radiotherap y ranging from seven months to eight years. Of the 16 patients with symptomatic radionecrosis, 11 (68, 75%) showed complete resolution of symptoms while five (31, 25%) showed improvement but still presented a neurological deficit at the closing date of the study. At the closing date, 11 patients (68.75%) had angiographically completely obliterated arterio venous malformations while another two patients had an obliteration of 95% to 98% and one patient had a 98% obliteration with development of a new contralateral AVM. In our series, symptomatic radionecrosis occurred in 7.1% of patients treated with stereotactic radiosurgery for brain AVM.

These patients where subjected to a prompt, high dose corticosteroid treatment and most presented symptom resolution or improvement with a fair obliteration rate, offering protection from bleeding. Permanent neurologic deficits attributable to radionecrosis occurred in 2.2% of our patient population treated with stereotactic radiosurgery for brain AVM.

Accurate knowledge of cerebral aneurysm volume would be valuable in guiding the volume of embolized material required for optimal filling of an aneurysm sac and recording percentage volume filling. Algebraic volumes are frequently estimated by algebraic volume formulae. 3D digital subtraction angiography (DSA) aids endovascular treatment planning and yields volumetric data. Our aim was to define the accuracy of 3D-DSA in quantifying aneurysm volume using an automated voxel-based volumetric method (voxel volume method) and compare results to volumes calculated by ellipsoid and cylindrical algebraic formulae (algebraic volume method).

We constructed 13 latex aneurysm moulds and measured their true volumes using a micro-pipette in-vitro. 3D-DSA was performed on contrast filled moulds and experimental volume estimated by both voxel and algebraic methods. In our in-vivo study we quantified the voxel and algebraic volumes from the 3D data sets of 75 cerebral aneurysms. The linear regression test provided correction values between voxel and algebraic methods.

The in-vitro study showed that the voxel volume method was the most accurate (mean percentage deviation from true volume 3.7 ± 3.5%; p = 0.9). The ellipsoid method significantly underestimated −11.2 ±13.6%; p<0.05) and the cylindrical method overestimated (42.6 ±35.7%; p<0.05) true aneurysm volume. Similar results were obtained in-vivo. While algebraic measurements could be corrected by an equation, the clinical usefulness of this equation is questionable due to the large volume range to achieve a 95% confidence interval.

The voxel volume method is accurate in quantifying aneurysm volume. Aneurysms in-vivo do not conform to simple algebraic geometry. Aneurysm volume on 3D-DSA should be calculated by the voxel-based method and not by algebraic formulae.

The vast majority of intracranial aneurysms can be obliterated completely with surgical clipping. However, postoperative remnants occur in about 4 to 8% of patients who undergo postoperative angiography.

Endovascular embolization has been successfully performed in patients with postoperative aneurysm remnant and it may represent a therapeutic alternative to surgical reintervention.

Twelve aneurysm remnants after surgical clipping were treated with endovascular embolization using GDC. All aneurysms were located in the anterior circulation. Our experience confirms the feasibility and relative safety of this treatment strategy that may be considered a valid alternative to reintervention.

Proximal occlusion of the vertebral artery is regarded as a safe and effective method of treating aneurysms of the vertebral artery or the vertebrobasilar junction unsuitable for treatment by neck clipping. Complications known to develop after this procedure include ischemic lesions of the perforators and other areas. There are only a limited number of reports on early rupture of aneurysm following proximal occlusion of the vertebral artery for the treatment of unruptured aneurysm. We recently encountered a case of large aneurysm of the vertebral artery identified after detection of brainstem compression. This patient underwent proximal occlusion of the vertebral artery with a coil and developed a fatal rupture of the aneurysm ten days after proximal occlusion.

The patient was a 72-year-old woman who had complained of dysphagia and unsteadiness for several years. An approximately 20 mm diameter aneurysm was detected in her left vertebral artery. She underwent endovascular treatment, that is, her left vertebral artery was occluded with coils at a point proximal to the aneurysm. Her initial post-procedure course was uneventful. However, she suddenly developed right-side hemiparesis nine days after procedure. At that time, CT scan suggested sudden thrombosis of the aneurysm. Right vertebral angiography revealed a small part of the aneurysm. She was treated conservatively. Ten days after the procedure, she suffered massive subarachnoid haemorrhage.

Both the present case and past reports suggest that proximal occlusion of the vertebral artery is effective in treating relatively large aneurysms unsuitable for treatment by neck clipping or trapping. However, when the bifurcation of the posterior inferior cerebellar artery (PICA) is distal to the occluded point in cases where the PICA bifurcates from the aneurysm or the neck region, blood supply to the aneurysm may persist because anterograde blood flow to the PICA may be preserved. Therefore, clinicians must consider the possibility of aneurysm rupture after proximal occlusion in the following cases:

1) when the aneurysm is large or giant, but non-thrombosed;

We report the case of a 49-year-old woman with a massive subarachnoid haemorrhage in conjunction with trauma. The initial cerebral angiography was normal. Three weeks later she had a second subarachnoid haemorrhage. A repeat angiography demonstrated an eight mm aneurysm of the internal carotid artery bifurcation, a region clearly normal in the previous angiography.

We report a patient with a wide-necked aneurysm arising at the bifurcation of the right internal carotid artery and the persistent primitive trigeminal artery (PPTA) treated successfully by Matrix detachable coil occlusion and assisted by a Neuroform intracranial stent. First, a Neuroform self-expanding intracranial stent was delivered via a 5-F Guider Softtip XP and placed as desired, then the aneurysm dome was embolized with two Matrix detachable coils through the interstices of the stent. The aneurysm was 80% occluded angiographically and the parent artery was patent. DSA imaging six months after the procedure showed the aneurysm to be obliterated at angiography and the neck tissue thickness of the aneurysm to be increased, but the parent artery diameter was not impacted. We describe the case in detail and discuss our preliminary experience of using the Neuroform stent and Matrix detachable coils for the treatment of a PPTA wide-necked aneurysm.

We demonstrate endovascular stent deployment for the treatment of atherosclerotic basilar artery occlusion with acute thrombosis. Application of a microstent without previous balloon dilatation resulted in vessel reopening and good clinical improvement. Emergency primary stent application can be technically feasible and improve the outcome in acute basilar artery occlusion and clinical status.

We report an unusual case of spinal dural arteriovenous fistula (SDAVF) presenting with subarachnoid haemorrhage (SAH). Cure was achieved with endovascular treatment with n-butyl 2-cyanoacrylate (NBCA). A review of the literature revealed five cases of cervical SDAVF that presented with SAH. None of these cases were treated with NBCA.

HHT (Hereditary Haemorrhagic Telangiectasia or Rendu Osler Weber disease) is a known autosomal dominant dysplasia. The first clinical presentation of HHT in a child may be a cerebral or spinal AVM. We present the case of a young boy with HHT who had a previous spinal cord AVF treated by surgical obliteration and then presented with a spinal dural AVF nine months later.

This patient had surgical obliteration of a spinal cord perimedullary AVF and subsequently developed a new spinal dural AVF at a different level. The diagnosis was made by spinal MR imaging and spinal angiography