Interventional Neuroradiology

Innovations in endovascular tools have permitted an increasingly broad range of neurovascular lesions to be treated via minimally invasive methods. However, some device modifications may carry additional risks, not immediately apparent to operators.

A patient with a symptomatic, partially thrombosed basilar apex aneurysm was allocated balloon-assisted coiling. Attempts were made to place a microwire across the basilar apex through the posterior communicating artery. Overlapping courses of the posterior cerebral and posterior choroidal arteries on the roadmap images were not recognized and a flanged-tip microwire was inadvertently advanced deep into the choroidal artery. Following the wire with a microcatheter led to binding of arterial tissue within the microcatheter. Removing the wire led to an avulsion of the choroidal artery and a severe hemorrhagic complication which proved fatal. Tissue was identified on the tip of the guidewire. Pathology showed layers of vascular tissue within the laser-cut flanges of the distal wire tip.

A similar complication, also fatal, occurred during balloon angioplasty of a distal vertebral artery, when an exchange wire was accidently introduced into a perforator from a posterior cerebral artery.

Ex vivo catheterization of distal mesenteric arterial branches showed that the wall of small arteries can be entrapped by laser-cut, flanged, but not by smooth guidewire tips.

Microwires with a flanged instead of smooth distal tip, when placed into small caliber vessels, may cause hemorrhagic complications from avulsions.

Arterial fenestrations are an anatomic variant with indeterminate significance. Given the controversy surrounding fenestrations we sought their prevalence within our practice along with their association with other cerebrovascular anomalies.

We retrospectively reviewed 10,927 patients undergoing digital subtraction angiography between 1992 and 2011. Dictated reports were searched for the terms “fenestration” or “fenestrated” with images reviewed for relevance, yielding 228 unique cases. A Medline database search from February 1964 to January 2013 generated 304 citations, 127 cases of which were selected for analysis.

Cerebral arterial fenestrations were identified in 228 patients (2.1%). At least one aneurysm was noted in 60.5% of patients, with an aneurysm arising from the fenestration in 19.6% of patients. Aneurysmal subarachnoid hemorrhage or non-aneurysmal subarachnoid hemorrhage were present in 60.1% and 15.8%, respectively. For the subset of patients with an aneurysm arising directly from a fenestration relative to those patients with an aneurysm not immediately associated with a fenestration, the prevalence of aneurysmal subarachnoid hemorrhage was 66.7% vs. 58.6% (p = 0.58). Fenestrations were more often within the posterior circulation (73.2%) than the anterior circulation (24.6%), though there was no difference in the prevalence of aneurysms within these groups (61.1% vs. 60.7%, p = 1.0).

Cerebral arterial fenestrations are an anatomic variant more often manifesting at the anterior communicating arterial complex and basilar artery and with no definite pathological relationship with aneurysms.

The application of high intense focused ultrasound (HIFU) is currently the subject of many experimental and clinical trials. The combination of HIFU with MRI guidance known as MR-guided focused ultrasound (MRgFUS) appears to be particularly promising to ablate tissues located deep in the brain. The method can be the beginning of interventional neurology and an important alternative to neurosurgery. Studies conducted to date show the effectiveness of the method both in chronic diseases and in emergency cases. The safety and effectiveness of this method have been observed in parkinsonian and essential tremor as well as in neuropathic pain. The procedure does not require anaesthesia. Ionizing radiation is not used and there is no risk of cumulative dose. Such advantages may result in low complication rates and medical justification for further development of MRgFUS.

We describe a case of arteriovenous fistula (AVF) successfully treated by coil embolization with an anchor coil inserted in the varix to facilitate dense packing at the shunting site. AVF of the left anterior choroidal artery (AChoA) draining into the ipsilateral basal vein of Rosenthal was incidentally found in a newborn female. A single detachable coil was inserted as an anchor into the varix adjacent to the shunt, and the microcatheter was pulled back to the shunting point. Three more detachable coils were delivered at the shunting point without migration under the support of the anchor coil, and the AVF was successfully obliterated with preservation of AChoA blood flow. The anchor coil technique can reduce the risk of coil migration and the number of coils required.

Coil embolization of oblong aneurysms is difficult because the majority of commercially available coils are manufactured with a helical or spherical tertiary structure. While adopting framing strategies for oblong aneurysms (aspect ratio ≥ 2: 1), traditional coils may be undersized in the long axis but oversized in the short axis, resulting in increased aneurysmal wall stress, risk of re-rupture, and difficulty creating a basket that respects the aneurysmal neck. We review three cases in which versatile filling coils (VFCs) were used as the initial coils for embolization of oblong aneurysms and report coil distribution characteristics and clinical outcomes. Packing density after VFC implantation was assessed using the software AngioSuite-Neuro edition and AngioCalc.

Illustrative case: a 58-year-old woman experienced a subarachnoid hemorrhage from a ruptured anterior communicating artery aneurysm (7.5 mm × 3.5 mm). A 3–6 mm × 15 cm VFC was selected as the first coil because the flexibility of its wave-loop structure facilitates framing of an irregularly shaped aneurysm. The loop portions of the structures tend to be pressed to the extremes of the aneurysmal sac by the wave component. The VFC was introduced smoothly into the aneurysmal sac without catheter kickback. We were then able to insert detachable filling coils without any adjunctive technique and achieved complete occlusion. Complete occlusion without severe complications was achieved in all three cases in our study. Average packing density after the first coil was 15.63%.

VFC coils may have a specific role in framing oblong aneurysms given their complex loop-wave design, allowing spacing of the coils at the dome and neck while keeping sac stress to a minimum.

Here we describe the case of a patient with a wide-necked unruptured aneurysm arising at origin of a persistent primitive trigeminal artery (PTA) variant from the right internal carotid artery (ICA), supplying the territory of the right superior cerebellar artery and the anterior inferior cerebellar artery. To preserve the ICA and the PTA variant, coil embolization of the aneurysm was performed using a double-balloon remodeling technique (HyperForm™ and Hyper-Glide™ Occlusion Balloon Systems; ev3 Endovascular Inc., Irvine, CA, USA). The association of a PTA variant with an aneurysm is very rare. To our knowledge, this is the first description of the use of coil embolization using double-balloon remodeling to treat a PTA variant aneurysm. This technique permits complete embolization and reduces the risk of cerebral and cerebellar ischemia.

Indirect (dural) carotid cavernous fistulae are generally treated by endovascular surgery primary transvenous embolization that is safe and effective. We describe here a case of a left indirect carotid cavernous fistula that presented with proptosis and eye redness. The patient underwent transvenous embolization of carotid cavernous sinus. The procedure was complicated by a haemorrhage from the cavernous sinus. The post procedural CT scan showed a haematoma at the tentorial edge. Precise diagnosis and prompt treatment could prevent severe complications.

We evaluated the outcomes of endovascular or surgical treatment of ruptured vertebral artery dissecting aneurysms (VADAs), and investigated the relations between treatment complications and the development and location of the posterior inferior cerebellar artery (PICA).

We treated 14 patients (12 men, two women; mean age, 56.2 years) with ruptured VADAs between March 1999 and June 2012 at our hospital. Six and eight patients had Hunt and Hess grades 1–3 and 4–5, respectively.

Twelve patients underwent internal endovascular trapping, one underwent proximal endovascular occlusion alone, and one underwent proximal endovascular occlusion in the acute stage and occipital artery (OA)-PICA anastomosis and surgical trapping in the chronic stage. The types of VADA based on their location relative to the ipsilateral PICA were distal, PICA-involved, and non-PICA in nine, two, and three patients, respectively. The types of PICA based on their development and location were bilateral anterior inferior cerebellar artery (AICA)-PICA, ipsilateral AICA-PICA, extradural, and intradural type in one, two, two, and nine patients, respectively. Two patients with high anatomical risk developed medullary infarction, but their midterm outcomes were better than in previous reports. The modified Rankin scale indicated grades 0–2, 3–5, and 6 in eight, three, and three patients, respectively.

A good outcome is often obtained in the treatment of ruptured VADA using internal endovascular trapping, except in the PICA-involved type, even with high-grade subarachnoid hemorrhage. Treatment of the PICA-involved type is controversial. The anatomical location and development of PICA may be predicted by complications with postoperative medullary infarction.

Functional outcome following emergent intra-arterial thrombectomy is variable and likely reflects the heterogeneous characteristics of acute stroke patients.

The aims of our study were (1) to study which pre-treatment variables correlate with functional outcome and (2) to devise a tool which would reliably predict outcome.

Prospective data of patients treated with intra-arterial mechanical thrombectomy in our institution between 2010 and 2012 were collected. A preliminary univariate analysis of baseline variables was performed and data outliers were identified by constructing scatter and box plots.

Systematic bivariate analysis was then carried out using a linear regression model and the individual contributing weights of the variables to outcome calculated. The B and constant values from the regression were used to construct a predictive formula.

Fifty-seven patients, 35 males (61.4%) and 22 females (38.6%) with a mean age of 62.3 years (range 26–87) were included in the cohort. Statistical correlations of baseline variables and functional outcome showed that age, National Institutes of Health Stroke Scale at presentation and CT leptomeningeal collaterals were strongly correlated (p<0.01), and were later included in the linear regression model. A tool was devised from the regression formula combining weighted inputs of the three variables. Regression statistics and residual analysis were then performed to assess the accuracy and reliability of the proposed tool.

The proposed tool is easy to use and reliably predicts functional outcome prior to endovascular therapy. It may help clinical decision-making in the acute setting and offers ‘tailor-made’ outcome expectations.

Few reports have described the successful treatment of stroke caused by acute vertebral artery (VA) origin occlusion by endovascular surgery. We describe the case of a 68-year-old man who experienced stroke due to left acute VA origin occlusion. Cerebral angiography showed that the left VA was occluded at its origin, the right VA had hypoplastic and origin stenosis, and the basilar artery was occluded by a thrombus. The VA origin occlusion was initially passed through with a 0.035-inch guide wire. An angioplasty was performed, and a coronary stent was appropriately placed. The VA origin was successfully recanalized. A balloon-assisted guiding catheter was navigated through the stent and a thrombectomy was performed using the Penumbra system. The patient's symptoms gradually improved postoperatively. Balloon-assisted catheter guidance through a vertebral artery stent permitted a successful thrombectomy using the Penumbra system and may be useful for treating stroke due to VA origin occlusion.

The purpose of this study was to evaluate the efficacy and safety of intra-arterial therapy as a rescue strategy after clinically failed intravenous thrombolysis (IVT) in acute ischaemic stroke patients.

We conducted a retrospective analysis of consecutive acute ischaemic stroke patients treated with rescue therapy. The results from this study group were compared with those obtained from a control group consisting of 260 consecutive patients treated with IVT alone.

The study group consisted of 52 patients with a mean age of 63 years and a median NIHSS score at admission of 17. Recanalization was achieved in 92% with a symptomatic haemorrhage rate of 9.6%. Rescue patients admitted with a severe stroke (NIHSS score >12) had a significantly better outcome at 90 days compared to patients with the same score but treated with IVT alone. No difference was seen for patients with a lower score at admission.

This study indicates that rescue therapy may increase the proportion of patients with independent outcome if presenting with a severe stroke (NIHSS score >12) without increasing the rate of symptomatic haemorrhage.

Small retrospective studies have shown the benefit of endovascular treatment with intrasinus thrombolysis (IST) or mechanical thrombectomy (MT) with/without IST (MT+/−IST) in cases of multifocal cerebral venous thrombosis (CVT).

Our study compares the mortality, functional outcome and periprocedural complications among patients treated with MT +/– IST versus IST alone.

We reviewed clinical and angiographic findings of 63 patients with CVT who received endovascular treatment at three tertiary care centers. Primary outcome variables were discharge mortality and neurological dysfunction, and intermediate (three months) and long-term (>six months) morbidity. The modified Rankin scale (mRS) was used to assess morbidity. mRS ≤1 was considered a good recovery. Neurological dysfunction was rated as neuroscore: 0, normal; 1, mild (ambulatory, communicative); 2, moderate (non-ambulatory, communicative); and 3, severe (non-ambulatory, non-communicative/comatose).

In patients who received IST alone, presenting neurological deficits were comparatively minor (p<0.001). When the two groups were adjusted for admission neuroscore, there was no statistical significance between discharge mortality [7(21%) versus 4(14%), p=0.228], neurological dysfunction (p=0.442), intermediate (p=0.336) and long-term morbidity (p=0.988). Patients who received MT +/- IST had a higher percentage of periprocedural complications without reaching statistical significance.

Compared to IST, MT was performed in severe cases with extensive sinus involvement. When adjusted for admission neurological dysfunction, both groups had similar mortality and discharge neurological dysfunction and similar intermediate and long-term morbidity.

Arterial ischaemic stroke is an important cause of morbidity in children. Timely diagnosis is necessary for acute stroke treatment but can be challenging in clinical practice. Due to a paucity of data there are no specific recommendations regarding the use of mechanical thrombectomy devices in current paediatric stroke guidelines. A 14-year-old boy presented with a severe acute left hemisphere stroke due to a proximal middle cerebral artery occlusion caused by emboli from an atrial myxoma. No clinical improvement was seen after administration of intravenous thrombolysis. Subsequent mechanical thrombectomy with a second-generation stent-based thrombectomy device resulted in successful recanalization and clinical improvement. To our knowledge, this is the first report of mechanical thrombectomy in a child with acute embolic stroke caused by atrial myxoma.

We describe a rare case of a combined traumatic pseudoaneurysm and arteriovenous fistula (AVF) of the middle meningeal artery (MMA) on a non-fractured site. A 24-year-old man was admitted to our hospital with head trauma. He underwent a craniotomy and removal of an epidural hematoma on the right side. Twenty-five days later, he complained of pulsatile tinnitus on the left non-fractured side. Angiography revealed a markedly dilated proximal MMA with flow shunting to the pterygoid plexus. We performed proximal occlusion on the proximal MMA for the traumatic pseudoaneurysm and the AVF of the MMA using coils. Although immediate angiography showed retrograde contrast filling from the collateral vessels into the distal part of the pseudoaneurysm, follow-up angiography revealed that the lesion had successfully disappeared.

This study includes 20 patients with 21 spinal perimedullary fistulae. There were nine Type IVa (42.8%) lesions, ten Type IVb (47.6%) and two Type IVc (9.5%) lesions. The dominant arterial supply was from the anterior spinal artery (47.6%), posterior spinal artery (19%) and directly from the radiculomedullary artery (28.5%). Sixteen lesions in 15 patients were treated by endovascular route using n-butyl-2-cyanoacrylate. Endovascular treatment was not feasible in five patients. Of the ten patients with microfistulae, catheterization failed/was not attempted in 40%, complete obliteration of the lesion was seen in 60% but clinical improvement was seen in 40% of patients. Catheterization was feasible in all ten patients with macrofistulae (nine type IVb and two type IVc lesions). Complete obliteration of the lesions was seen in 60% and residue in 30%. Clinical improvement was seen in 80% and clinical deterioration in 10%. In conclusion, endovascular glue embolization is safe and efficacious in type IVb and IVc spinal perimedullary fistulae and should be considered the first option of treatment. It is also feasible in many of the type IVa lesions.

We report our experience in treating the anterior condylar dural arteriovenous fistula (DAVF) and confirm the location of the coils in the follow-up images after successful endovascular treatment.

We retrospectively reviewed the 14 patients with anterior condylar DAVF treated successfully in our institute. Twelve of them had CT or MR follow-up images. All the patients had intravascular coiling of the fistula. Seven of our patients had retrograde drainage to different sinuses. Three had ocular symptoms as a clinical manifestation. We treated nine patients with coils alone (eight transvenous, one transarterial), four with adjuvant transarterial treatment with particles or liquid embolic for minimal residual after coiling packing. One patient had failed onyx treatment and successful treatment by following transvenous packing. All patients had total obliteration of the DAVF fistula on immediate post-procedure angiogram or on the follow-up images and no evidence of recurrence clinically. The mean follow-up period was 34.2 months (standard deviation=39.8). Twelve patients had computed images (CT alone in four, MR alone in five, both CT and MR in three). These findings were analyzed by four certified neuroradiologists. We found 100% of the coils at the anterior condylar veins inside the hypoglossal canal, 54.2% at the lateral lower clivus, and only 14.2% at the anterior condylar confluence which is ventrolateral to the anterior orifice of the hypoglossal canal.

Intravascular coiling is the treatment of choice in patients with anterior condylar DAVF. All the coils were found at the anterior condylar veins inside the hypoglossal canal after successful treatment.