Interventional Neuroradiology

A patient with a previously Y-stented giant left middle cerebral artery (MCA) bifurcation aneurysm returned with a recurrence.

A flow diverter (FD) was deployed through one limb of the high-porosity Y-stenting construction. The proximal FD failed to expand and an attempt at balloon angioplasty led to fatal rupture of the MCA.

Autopsy demonstrated subarachnoid hemorrhage, vessel rupture and fracture of the proximal high-porosity stent. Microscopic photographs showed that the FD had failed to open because the guiding wire had inadvertently exited and re-entered the proximal segment of the high-porosity stent partially incorporated to the wall of the MCA. Balloon dilatation of the FD which had remained collapsed between the stent and the vessel wall caused fracture of the stent and rupture of the artery.

Angioplasty and flow-diversion of previously Y-stented aneurysms can lead to serious complications.

The objective of this article is to explore the feasibility of low injection rate and low contrast agent dose in three-dimensional rotational digital subtraction angiography (3D DSA) of the intracranial aneurysm.

Fifty-one patients with suspected intracranial aneurysms were included. The catheter tip was kept within the internal carotid artery at the epistropheus level. Patients were divided into three groups randomly according to injection rate: group A (1.5 ml/s, n = 18), group B (2.0 ml/s, n = 18), and group C (3.0 ml/s, n = 15). The noise, signal-to-noise ratio (SNR), and carrier-to-noise ratio (CNR) of C2, C6, M1, and A1 segments were calculated. The continuous subtraction images and reconstructed images were evaluated by two technicians.

No significant differences were found in noise between groups A and B, and groups A and C. Significant differences were found in the SNR and CNR of M1 and A1 segments between groups A and B, and groups B and C, but for C2 and C6 segments, they were not significant. Significant differences were found in the SNR and CNR of all segments between groups A and C. Significant differences were found in the contrast agent dose between all three groups. No significant differences were found in scores evaluated by two physicians between the three groups.

The personalized injection protocol of low injection rate and low contrast agent dose in 3D DSA of the intracranial aneurysm is feasible. The application of this protocol can reduce the dose of iodine and obtain satisfactory images.

Microsurgical clipping is a widely used surgical technique in intracranial aneurysm treatment. It can be difficult in large sized aneurysms, and those with wide necks, thick walls and calcification located in the vicinity of the neck. This study reviewed calcification of the intracranial aneurysm wall and its relation to patient age, gender, location and size of the aneurysm. A possible cut-off value after which the aneurysm calcification rate increases was also investigated to classify patients’ risk factors for microclipping.

A retrospective review of all unruptured intracranial aneurysms that underwent digital subtraction angiography at a single centre was performed. Flat-detector computed tomography images of the aneurysm were reviewed for aneurysm location, size and calcification. The independent samples t test and χ² test were used to show the relation between aneurysm wall calcification and patient age, gender, aneurysm localisation and size.

None of the reviewed factors were statistically significantly related to aneurysm calcification except aneurysm size (P < 0.01). Receiver operating characteristic curves showed aneurysms greater than 10.5 mm could be predicted to be calcified with a sensitivity of 80% and specificity of 63%.

In this study, the presence of calcification was related to aneurysm size. Larger aneurysms were more likely to be calcified. Aneurysms greater than 10.5 mm should be further investigated with a modality such as flat-detector computed tomography to show the calcification in detail, especially if microclipping is considered.

Recent data have demonstrated that mechanical thrombectomy (MT) is beneficial for patients presenting within zero to six hours of symptom onset after stroke. However, transferring all patients with possible strokes for endovascular therapy and MT would be inefficient and costly. We conducted a case-control study to identify a subset of the National Institutes of Health Stroke Scale (NIHSS) to identify patients with large-vessel occlusion (LVO) to a high degree of specificity, in order to select those patients for whom transfer is most appropriate.

Acute code stroke alerts presenting to a comprehensive stroke center from 2012 to 2013 (779) and corresponding NIHSS were collected. All patients had vascular imaging and 125 demonstrated LVO (cases) and were compared to 272 small-vessel strokes and stroke mimics (controls). Demographics of both groups and modified receiver operating characteristic (ROC) curves were generated for each combination of three NIHSS items to optimize specificity of LVO for those who would benefit from MT.

The average NIHSS of cases was higher than controls (12.5 vs. 6.5, p < 0.0001). The subset of three NIHSS items with the largest modified AUC (optimized for specificity) was maximum “Arm,” “Sensory,” and “Extinction.” Using a cutoff of seven out of a total 10 possible points, the sum score for these items has 90.2% specificity and 16.0% sensitivity for LVO.

We present a validated three-question subset of the NIHSS for those who would benefit from MT with a high degree of specificity.

The objective of this study was to add more evidence about the efficacy and safety of mechanical thrombectomy in patients with basilar artery occlusion and secondarily to identify prognostic factors.

Twenty-two consecutive patients (mean age 60.5 years, 15 men) with basilar artery occlusion treated with mechanical thrombectomy were included. Clinical, procedure and radiological data were collected. Primary outcomes were the modified Rankin scale score with a good outcome defined by a modified Rankin scale score of 0–2 and mortality rate at three months.

The median National Institutes of Health stroke scale at admission was 24 (interquartile range 11.5–31.25). Twelve patients (54.5%) required tracheal intubation due to a decreased level of consciousness. Successful recanalisation (modified treatment in cerebral ischaemia scale 2b–3) was achieved in 20 patients (90.9%). A favourable clinical outcome (modified Rankin scale score 0–2) was observed in nine patients (40.9%) and the overall mortality rate was 40.9% (nine patients). Haemorrhagic events were observed in three patients (13.63%). A decreased level of consciousness requiring intubation in the acute setting was more frequent in patients with poor outcomes (84.6%) than in patients with favourable outcomes (11.1%), and in patients who died (100%) compared with those who survived (23.1%), with a statistically significant difference (P = 0.002 and P = 0.001, respectively).

Mechanical thrombectomy is feasible and effective in patients with acute basilar artery occlusion. A decreased level of consciousness requiring tracheal intubation seems to be a prognostic factor and is associated with a poor clinical outcome and higher mortality rate. These initial results must be confirmed by further prospective studies with a larger number of patients.

To investigate the safety and long-term effect of using the Wingspan stent for severe symptomatic atherosclerotic basilar artery stenosis (≥70%).

Between July 2007 and April 2013, we had 91 consecutive patients (age range 41–82 years old) with symptomatic severe basilar stenosis (70–99%) who underwent Wingspan stenting at our center. All patients had stenosis-related temporary ischemic attack or strokes. We analyzed the demographic data, pre- and post-procedural cerebral angiography, technical success rate, peri-procedural complications, and clinical and imaging follow-ups.

The Wingspan stenting procedure was successful in all patients: The stenosis was reduced from 82.2% ± 5.8% pre-stenting to 15.9% ± 5.7% post-stenting. The 30-day peri-operative rate for stroke or death was 14.3%, which included ischemic stroke in 12 cases (12/91 = 13.2%) and subarachnoid hemorrhage in one case (1/91 = 1.1%), with a fatal or disabling stroke rate of 2.2%. Among the 77 patients with clinical follow-up assessment within 7–60 months (mean 31.3 ± 15.1 months) after stenting, four patients (5.2%) had posterior ischemia, including one patient with disabling ischemic stroke (1.3%) and three patients (3.9%) with temporary ischemic attack. The 2-year cumulative stroke rate was 16% (95% CI: 8.2–23.8%). Among 46 patients with imaging assessments at 3–45 months (mean, 9.5 ± 8.3) post-stenting, six (13.0%) patients had restenosis, including two (2/46 = 4.3%) with symptomatic restenosis.

The benefit of stenting for patients with severe basilar artery stenosis (> 70%) may lie in lowering the long-term fatal and disabling stroke rate; and as long as the peri-operative stroke rate can be kept at a relatively lower level, patients with severe basilar stenosis can benefit from basilar artery stenting.

A new generation of highly navigable large-bore aspiration catheters and retriever devices for intracranial mechanical thrombectomy has markedly improved recanalization rates, time and clinical outcomes. We report collected clinical data utilizing a new technique based on combined large lumen aspiration catheter and partially resheathed stent retriever (ARTS: Aspiration (catheter)–(stent) Retriever Technique for Stroke). This technique is applied, especially in presence of bulky/rubbery emboli, when resistance is felt while retracting the stent retriever; at that point the entire assembly is locked and removed in-toto under continuous aspiration with additional flow arrest.

A retrospective data analysis was performed to identify patients with large cerebral artery acute ischemic stroke treated with ARTS. The study was conducted between August 2013 and February 2015 at a single high volume stroke center. Procedural and clinical data were captured for analysis.

Forty-two patients (median age 66 years) met inclusion criteria for this study. The ARTS was successful in achieving Thrombolysis in Cerebral Infarction (TICI) ≥2b revascularization in 97.6% of cases (TICI 2b = 18 patients, TICI 3 = 23 patients). Patients’ median National Institutes of Health Stroke Scale score at admission was 18 (6–40). A 3-month follow-up modified Rankin Scale value of 0–2 was achieved in 65.7% of the successfully treated patients (average 2.4). Two patients (4.8%) developed symptomatic intraparenchymal hemorrhages. Six procedure unrelated deaths were observed.

We found that ARTS is a fast, safe and effective method for endovascular recanalization of large vessel occlusions presenting within the context of acute ischemic stroke.

Five randomized controlled trials (RCTs) on endovascular therapy (EVT) of stroke have proven a clinical benefit over conservative treatment or IV-thrombolysis alone. Lesional clot aspiration with a dedicated system can achieve revascularization without an additional retriever (a direct-aspiration first-pass technique, ADAPT), and the SOFIA has been shown to be both safe and efficacious in a multicentric retrospective study. We have evaluated a subset of these data acquired in two major stroke centers with regard to using the SOFIA for first-line lesional aspiration.

Thirty patients with large-vessel occlusions treated with first-line lesional aspiration were identified. Procedural data, clot length, reperfusion success (mTICI), procedural timings, complications, and clinical status at admission, discharge and at 90 days were analyzed.

The median baseline NIHSS was 16. IV thrombolysis was administered in 15/30 patients. Ninety-three percent of occlusions were in the anterior circulation. TICI ≥ 2b was achieved in 90% of multimodality treatments; lesional aspiration was successful in 67% within a median time of 20 minutes. The highest first-attempt success rate was in MCA occlusions (median time to recanalization 10 minutes). There were no device-related events. Symptomatic intracerebral hemorrhage (sICH) occurred in 10%, but never with sole lesional aspiration. Embolization to new territories was recorded in 1/30 (3%). Median discharge NIHSS was 7; 30% were mRS ≤ 2 at discharge and 43% at 90-day follow-up.

Lesional aspiration with SOFIA is in line with published data. The SOFIA may be used as a first-line device, aiming at fast recanalization by sole aspiration with good safety and efficacy. If unsuccessful, it converts into part of a stent retriever-based multimodality treatment.

In symptomatic subclavian steal syndrome, endovascular treatment is the first line of therapy prior to extra-anatomic surgical bypass procedures. Subintimal recanalization has been well described in the literature for the coronary arteries, and more recently, in the lower extremities. By modifying this approach, we present a unique retrograde technique using a heavy tip microwire to perform controlled subintimal dissection.

We present two cases of symptomatic subclavian steal related to chronic total occlusion of the left subclavian artery and right innominate artery, respectively. Standard crossing techniques were unsuccessful. Commonly at this point, the procedures would be aborted and open surgical intervention would have to be pursued. In our cases, retrograde access was easily achieved via an ipsilateral retrograde radial artery, using controlled subintimal dissection and a heavy-tipped wire.

We were able to easily achieve recanalization in both attempted cases of chronic total occlusion of the subclavian and innominate artery, using a retrograde radial subintimal approach. Subsequent stent-supported angioplasty resulted in complete revascularization. No major complications were encountered during the procedures; however, one patient did develop thromboembolic stroke secondary to platelet aggregation to the stent graft, 9 days post-procedure.

Endovascular treatment is considered the first-line intervention in medically refractory patients with symptomatic subclavian steal syndrome. In the setting of chronic total occlusions, a retrograde radial subintimal approach using a heavy tip wire for controlled subintimal dissection is a novel technique that may be considered when standard approaches and wires have failed.

Although rare, spinal arteriovenous malformations (AVMs) are thought to be more prevalent in the hereditary Hereditary Hemorrhagic Telangiectasia (HHT) population.

We report a case of a spinal AVM in a 37-year-old female with HHT treated with endovascular embolization. In addition, we report findings from a systematic review of the literature on the clinical characteristics, angioarchitecture, and clinical outcomes of HHT patients with spinal AVMs.

The patient is a 37 year-old female with definite HHT who presented with a one-year history of progressive gait difficulty. The spinal fistula was incidentally detected on chest computed tomography (CT). Spinal angiography demonstrated a large perimedullary arteriovenous fistula was supplied by a posterolateral spinal artery. The fistula was treated with detachable coils. The patient made a complete neurological recovery. Our systematic review yielded 25 additional cases of spinal AVMs in HHT patients. All fistulae were perimedullary (100.0%). Treatments were described in 24 of the 26 lesions. Endovascular-only treatment was performed in 16 cases (66.6%) and surgical-only treatment was performed in five cases (20.8%). Complete or near-complete occlusion rates were 86.7% (13/15) for endovascular treated cases, 100.0% (4/4) for surgery and 66.6% (2/3) for combined treatments. Overall, 80.0% of patients (16/20) reported improvement in function following treatment, 100.0% (5/5) in the surgery group and 84.6% (11/13) reported improvement in the endovascular group.

Spinal fistulae in HHT patients are usually type IV perimedullary fistulae. Both endovascular and surgical treatments appeared to be effective in treating these lesions. However, it is clear that endovascular therapy has become the preferred treatment modality.

In interventional neuroradiology, few operators routinely use radiation protection glasses. Moreover, in most centers, radiation dose data only accounts for whole body dose without specific information on lens dose. In 2012, the International Commission on Radiological Protection advised that the threshold limit value for the lens should be 20 mSv/year instead of the previous 150 mSv/year limit. The purpose of this study was to compare the radiation dose in the operator’s lens during real diagnostic and interventional neuroangiographies, either using or without lead protection glasses.

Using the Educational Direct Dosimeter (EDD30 dosimeter), accumulated radiation dose in the lens was measured in 13 neuroangiographies: seven diagnostic and six interventional. Operators with and without radiation protection glasses were included and the sensor was placed near their left eye, closest to the radiation beam.

Without glasses, the corrected mean dose of radiation in the lens was 8.02 µSv for diagnostic procedures and 168.57 µSv for interventional procedures. Using glasses, these values were reduced to 1.74 µSv and 33.24 µSv, respectively.

Considering 20 mSv as the suggested annual limit of equivalent dose in the lens, neuroradiologists may perform up to 2,494 diagnostic procedures per year without protecting glasses, a number that increases to 11,494 when glasses are used consistently. Regarding intervention, a maximum of 119 procedures per year is advised if glasses are not used, whereas up to 602 procedures/year may be performed using this protection. Therefore, neuroradiologists should always wear radiation protection glasses.