CT reconstruction and MRI fusion of 3D rotational angiography in the evaluation of pediatric cerebrovascular lesions.

PURPOSE: Complex neurovascular lesions in children require precise anatomic understanding for treatment planning. Although 3DRA is commonly employed for volumetric reformation in neurointerventional procedures, the ability to reconstruct this data into CT-like images (3DRA-CT) is not widely utilized. This study demonstrates the feasibility and usefulness of 3DRA-CT and subsequent MRI fusion for problem solving in pediatric neuroangiography. METHODS: This retrospective study includes 18 3DRA-CT studies in 16 children (age 9.6 ± 3.8 years, range 2-16 years) over 1 year. After biplane 2D-digital subtraction angiography (DSA), 5-second 3DRA was performed with selective vessel injection either with or without subtraction. Images were reconstructed into CT sections which were post-processed to generate multiplanar reformation (MPR) and maximum intensity projection (MIP) images. Fusion was performed with 3D T1 MRI images to precisely demonstrate neurovascular relationships. Quantitative radiation metrics were extracted and compared against those for the entire examination and for corresponding biplane 2D-DSA acquisitions. RESULTS: In all 18 cases, the 3DRA procedure and MRI fusion were technically successful and provided clinically useful information relevant to management. The unsubtracted and subtracted 3DRA acquisitions were measured to deliver 5.9 and 132.2%, respectively, of the mean radiation dose of corresponding biplane 2D-DSA acquisitions and contributed 1.2 and 12.5%, respectively, to the total procedure dose. CONCLUSION: Lower radiation doses, high spatial resolution, and multiplanar reformatting capability make 3DRA-CT a useful adjunct to evaluate neurovascular lesions in children. Fusing 3DRA-CT data with MRI is an additional capability that can further enhance diagnostic information.

First line transradial access for posterior circulation stroke intervention; initial 12-month experience at a high volume thrombectomy center.

BACKGROUND: The Neurointerventional Surgery Standards and Guidelines Committee has advocated the use of transradial access in the setting of posterior circulation stroke intervention, however there is a paucity of published data on this approach. The purpose of this study is to present 12-months of prospectively collected data from a high volume thrombectomy center following the adoption of a first line transradial approach for posterior circulation stroke intervention. METHODS: A range of data on patient characteristics, procedural metrics, complications and outcomes was prospectively collected between August 2018 - August 2019 following the adoption of first line transradial access for posterior circulation stroke intervention at a high volume thrombectomy center. RESULTS: Transradial access was successful in 22/23 cases (96%), median arteriotomy to reperfusion time was 24 min (IQR 18-40), good angiographic outcome (mTICI 2b-3) was achieved in all cases and good clinical outcome (mRs 0-2) was achieved in 61% of cases. No intracranial or radial artery access site complications occurred. CONCLUSION: The fast procedure times, excellent outcomes and low complication rates achieved in this prospective 12-month study indicate that transradial access is a viable first line strategy in posterior circulation stroke intervention.

Air retrieval for clot retrieval; time-metrics and outcomes of stroke patients from rural and remote regions air-transported for mechanical thrombectomy at a state stroke unit.

BACKGROUND: Providing thrombectomy services to rural or remote regions with small, dispersed populations presents a particular challenge. Sustaining local thrombectomy services is not viable given the low throughput of cases, therefore large vessel occlusion (LVO) stroke patients require emergent transfer, often by air, to the closest high volume urban thrombectomy unit. The aim of this paper is to present logistical, time-metric data and outcome data on LVO stroke patients that have been aeromedically retrieved for thrombectomy from the vast, 2,500,000-km2 rural catchment of the Western Australian state thrombectomy unit. METHODS: The prospectively collected state thrombectomy registry was reviewed and all patients that underwent thrombectomy for LVO strokes following aeromedical retrieval from remote or rural catchments were identified. Multiple logistic and time-metric data points were recorded and outcomes were compared to a cohort of urban patients treated over the same period. RESULTS: Over a 2-year period 30 patients underwent thrombectomy following aeromedical retrieval, either by helicopter or fixed wing aircraft, from rural and remote regions of Western Australia. The mean aeromedical retrieval distance was 393 km while the maximum retrieval distance was over 2600 km. The mean ictus to recanalization time was 657 min, an mTICI 2b-3 recanalization was achieved in 93% of cases and 62% of anterior circulation, and 50% of posterior circulation LVO stroke patients achieved functional independence at 90-days. Outcome data for rural patients compared favourably to urban patients treated over the same time period. CONCLUSION: With the availability of an efficient aeromedical retrieval service, LVO stroke patients in rural and remote regions can achieve excellent outcomes following transfer to a high volume thrombectomy unit, even if distances involved are very large.

Thrombectomy in stroke of unknown onset, wake up stroke and late presentations: Australian experience from 2 comprehensive stroke centres.

Two recent randomized controlled trials (RCTs) showed selected patients treated with endovascular thrombectomy (EVT) more than 6 h from acute ischemic stroke (AIS) onset had significant improvement in functional outcome at 90 days compared with standard care alone. Our aim is to determine the outcome and predictors of good outcome in AIS patients undergoing EVT with unknown-onset, or late presentation, stroke after 6 h from time last seen well, or witnessed stroke onset, at two Australian comprehensive stroke centres. A retrospective analysis of functional outcome and mortality at 90-days from a prospective cohort of 56 consecutive patients with unknown-onset, or late presentation, stroke with large vessel occlusion (LVO) in the anterior cerebral circulation undergoing EVT over a 15-month period (2016-2017). We evaluated factors which correlated with good functional outcome defined as a 90-day modified Rankin scale (mRS) 0-2. Recanalization times and symptomatic intracranial haemorrhage (sICH) rates were also examined. A good functional outcome was achieved in 35 patients (62%). Eight patients died (14%). Median time-to-recanalization was 7.6 h. SICH occurred in four patients (7%). Factors which predicted good 90-day functional outcome included baseline National Institutes of Health Stroke Scale (NIHSS) < 16, 24 h NIHSS < 10, baseline Alberta Stroke Program Early CT Score (ASPECTS) ≥ 8, pre-procedural CT perfusion imaging and LVO lesion location. This study shows good 'real world' outcomes, comparable to published RCTs, in patients with unknown-onset, or late presentation, stroke treated with EVT more than 6 h from stroke onset.

The second-generation eCLIPs Endovascular Clip System: initial experience.

OBJECTIVE Treatment of wide-necked intracranial aneurysms is associated with higher recanalization and complication rates; however, the most commonly used methods are not specifically designed to work in bifurcation lesions. To address these issues, the authors describe the evolution in the design and use of the eCLIPs (Endovascular Clip System) device, a novel hybrid stent-like assist device with flow diverter properties that was first described in 2008. METHODS A registry was established covering 13 international centers at which patients were treated with the second-generation eCLIPs device. Aneurysm morphology and rupture status, device neck coverage, coil retention, and procedural and late morbidity and mortality were recorded. For those patients who had undergone successful implantation more than 6 months earlier, the final imaging and clinical follow-up results and need for re-treatment were recorded. RESULTS Thirty-three patients were treated between June 2013 and September 2015. Twenty-five (76%) patients had successful placement of an eCLIPs device; 23 (92%) of these 25 patients had complete data. Eight cases of nondeployment occurred during the 1st year of use, consistent with a learning curve; no failures of deployment occurred thereafter. Two periprocedural transient ischemic attacks and 2 asymptomatic thrombotic events occurred. Twenty-one (91%) of 23 patients underwent follow-up at an average of 8 months (range 3-18 months); 9 (42.9%) of these 21 patients demonstrated an improvement in Raymond grade at follow-up; no cases of worsening Raymond grade were recorded, and 17 (81.0%) patients sustained a modified Raymond-Roy Classification class of I or II angiographic result at follow-up. Two delayed ruptures were recorded, both in previously coiled, symptomatic giant aneurysms where the device was used as a part of a salvage strategy. CONCLUSIONS The second-generation eCLIPs device is a viable treatment option for bifurcation aneurysms. The aneurysm occlusion rates in this initial clinical series are comparable to the initial experience with other bifurcation support devices.

Entry remnants in flow-diverted aneurysms: Does branch geometry influence aneurysm closure?

OBJECTIVE: Numerous studies have suggested a relationship between delayed occlusion of intracranial aneurysms treated with the Pipeline Embolization Device (PED) and the presence of an incorporated branch. However, in some cases, flow diversion may still be the preferred treatment option. This study sought to determine whether geometric factors pertaining to relative size and angulation of branch vessel(s) can be measured in a reliable fashion and whether they are related to occlusion rates. METHODS: Eighty aneurysms treated at a single neurovascular center from November 2008 to June 2014 were identified. Two blinded raters prospectively reviewed the imaging performed at the time of the procedure and measured the following geometric variables: inflow jet/incorporated branch direction angle and branch artery/ parent artery ratio. Delayed occlusion was defined as the absence of complete aneurysmal occlusion at one year. Analysis was performed using logistic regression and intra-class correlation co-efficient (ICC). RESULTS: Twenty-four (30%) aneurysms with 28 incorporated branches were identified. A trend toward higher inflow jet/incorporated branch direction angle was found in the group of aneurysms demonstrating delayed occlusion when compared to the group with complete occlusion. ICC revealed high correlation. Overall lower one-year occlusion rates of 53% versus 73% for aneurysms with and without incorporated branches, respectively, were also noted. CONCLUSIONS: The presence of an incorporated branch conferred a 20% absolute risk increase for delayed aneurysmal occlusion. Incorporated branches with a larger angle between the inflow jet and the incorporated branch direction exhibited a trend toward lower occlusion rates. This might be further investigated using a multicenter approach in conjunction with other potentially relevant clinical and angiographic variables.

Successful endovascular thrombectomy 90h after stroke onset.

Endovascular thrombectomy (EVT) has extended the conventionally accepted time window of treatment, from 4.5h (ECASS III trial) for intravenous thrombolysis, to 7.3h for EVT (HERMES collaboration). More recent evidence suggests EVT times could be extended to 24h in carefully selected patients (DAWN trial). Some patients present after these time windows with large areas of ischemia but little established infarction on imaging. They represent a major dilemma with much to gain from EVT but at theoretically higher risk of a poor outcome. We present a case of near-complete left M1 occlusion in which EVT achieved reperfusion 90h 41min after stroke onset with excellent clinical outcome. Current guidelines on treatment windows for EVT according to HERMES collaboration do not reflect individual patient factors. In appropriate patients delayed EVT may give positive clinical outcomes.

Ultra-Early Angiographic Vasospasm After Aneurysmal Subarachnoid Hemorrhage: A Systematic Review and Meta-Analysis.

OBJECTIVE: After aneurysmal subarachnoid hemorrhage (aSAH), prognosis is affected heavily by the presence of delayed cerebral ischemia (DCI). There is growing recognition of ultra-early angiographic vasospasm (UEAV) occurring within 48 hours of aSAH; however, its relationship with DCI and ultimately prognosis remains unclear. METHODS: Various databases limited to the English language through September 2016 were searched systematically. Eligible studies were those comparing UEAV with control non-UEAV outcomes and follow-up. Two independent reviewers evaluated the quality of studies and abstracted the data, with discrepancies resolved by a third. We calculated odds ratios (ORs) and 95% confidence intervals for all outcomes by using random-effects meta-analyses and performed a heterogeneity analysis. RESULTS: Four comparative studies were selected for analysis. Pooled analysis demonstrated that UEAV compared with no-UEAV was associated with greater proportion of rupture aneurysms sized greater than 12 mm (38.3% vs. 24.3%, P < 0.00001). A significantly greater number of patients with UEAV had ruptured MCA aneurysms compared with patients without UEAV (29.7% vs. 19.9%, P = 0.005). Compared with no-UEAV, patients with UEAV were significantly associated with symptomatic cerebral vasospasm (OR 2.07, P = 0.05) and DCI/infarction (OR 2.52, P = 0.02). A significant association also was found between UEAV and an unfavorable outcome at follow-up (OR 1.64, P = 0.03) and greater mortality (OR 2.65, P < 0.00001). CONCLUSIONS: UEAV was significantly associated with symptomatic cerebral vasospasm, DCI/infarction, unfavorable outcome at follow-up, and greater mortality. Patients with intracerebral hematoma, intraventricular hemorrhage (Fisher Grade IV), larger ruptured aneurysms >12 mm, and an MCA location were more likely to have UEAV.

CT perfusion in acute stroke calls: A pictorial review and differential diagnoses.

CT perfusion is increasingly utilised in hyperacute stroke to facilitate diagnosis and patient selection for reperfusion therapies. This review article demonstrates eight examples of how CT perfusion can be used to diagnose stroke mimics and small volume infarcts, which can be easily missed on non-contrast CT, and to suggest the presence of an ischaemic penumbra. Radiologists involved in stroke management must understand the importance of rapid imaging acquisition and be confident in the prospective interpretation of this powerful diagnostic tool as we move into a new era of hyperacute stroke care.

Micro-bubble transcranial Doppler ultrasound for exclusion of right-to-left circulatory shunts: why should we provide the service?

Micro-bubble transcranial Doppler ultrasound is a study used for the identification and quantification of a right-to-left circulatory shunt which can be implicated in stroke. It is an underused technique in many centres. Micro-bubble transcranial Doppler ultrasound is non-invasive, innocuous, quick and requires no fasting or sedation. Published literature also suggests almost perfect concordance with transoesophageal echocardiography and potentially greater sensitivity. We believe there is a great potential for neuroradiologists to provide this service as part of the diagnostic workup in patients with cryptogenic stroke.

Cost analysis of intracranial aneurysmal repair by endovascular coiling versus flow diversion: at what size should we use which method?

INTRODUCTION: Flow diverters enable intracranial aneurysmal repair without the need to enter the aneurysm sac. Concerns, however, have been raised regarding the cost compared with coiling techniques. The aim of this study was to evaluate the relative costs for different aneurysm sizes to ascertain if different sizes are more cost-effectively treated by a particular method. METHODS: Patients undergoing aneurysmal repair at two neurovascular referral centres between September 2005 and August 2010 were included; patients who underwent coiling for recurrences of prior microneurosurgical clipping were excluded. These aneurysms were stratified into three size groups. The average and median number of coils or flow diverters and the average and median costs of treatment of each size category were calculated. RESULTS: Four hundred twenty-nine aneurysms were treated. Of these, 409 were coiled with or without assist devices. Forty-eight percent fell under Group A (<7 mm), 36% under Group B (7-12 mm) and 16% under Group C (>12 mm). Twenty aneurysms were flow diverted. Of these, 14 were treated de novo, five previously coiled and one previously clipped. Twenty percent belonged in Group A, 25% in Group B and 55% in Group C. The highest procedural costs in the coiling group were Group C aneurysms requiring stent assistance, with an average of $24 563 (median $23 860). Using flow diversion, the average was $24 650 (median $16 490). CONCLUSION: Given the price parity threshold crossed for aneurysms >12 mm requiring stent assistance and the relative ease of the flow diverter technique, we suggest that flow diversion should be considered the first-line treatment for aneurysms in this category.