Brain MRI findings in neurologically symptomatic COVID-19 patients: a systematic review and meta-analysis.

BACKGROUND: Coronavirus disease 2019 (COVID-19) has been associated with nervous system involvement, with more than one-third of COVID-19 patients experiencing neurological manifestations. Utilizing a systematic review, this study aims to summarize brain MRI findings in COVID-19 patients presenting with neurological symptoms. METHODS: Systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) checklist. The electronic databases of PubMed/MEDLINE, Embase, Scopus, and Web of Science were systematically searched for literature addressing brain MRI findings in COVID-19 patients with neurological symptoms. RESULTS: 25 publications containing a total number of 3118 COVID-19 patients with neurological symptoms who underwent MRI were included. The most common MRI findings and the respective pooled incidences in decreasing order were acute/subacute infarct (22%), olfactory bulb abnormalities (22%), white matter abnormalities (20%), cerebral microbleeds (17%), grey matter abnormalities (12%), leptomeningeal enhancement (10%), ADEM (Acute Disseminated Encephalomyelitis) or ADEM-like lesions (10%), non-traumatic ICH (10%), cranial neuropathy (8%), cortical gray matter signal changes compatible with encephalitis (8%), basal ganglia abnormalities (5%), PRES (Posterior Reversible Encephalopathy Syndrome) (3%), hypoxic-ischemic lesions (4%), venous thrombosis (2%), and cytotoxic lesions of the corpus callosum (2%). CONCLUSION: The present study revealed that a considerable proportion of patients with COVID-19 might harbor neurological abnormalities detectable by MRI. Among various findings, the most common MRI alterations are acute/subacute infarction, olfactory bulb abnormalities, white matter abnormalities, and cerebral microbleeds.

Balloon Gliding Technique: A novel use of balloon guiding catheters in accessing challenging circulations when treating acute ischemic stroke.

BACKGROUND: Challenging arterial anatomy delays, or prevents timely endovascular treatment (EVT) of acute ischemic stroke (AIS). We introduce a new technique called 'Balloon Gliding Technique (BGT)' to overcome difficult arterial anatomy during EVT of AIS, utilizing flow-assistance to access challenging circulations. METHODS: Retrospective review of a prospectively collected database of all patients presenting to a single institution with AIS who underwent EVT was performed from January 2021 to June 2021. Patients in whom BGT was performed were assessed. BGT consists of advancing the balloon guide catheter in the cervical carotid artery while its balloon is inflated, and therefore carried by downstream flow. RESULTS: Of 51 patients presenting with AIS secondary to large vessel occlusion during the study period, five patients underwent BGT. All five patients had anterior circulation large vessel occlusions. Mean age of the BGT patients was 92.2 years, and all patients were females. A type 3 arch was present in all patients. BGT was performed in all cases following initial failure of conventional techniques to cannulate the target circulation. BGT was successful in achieving distal cervical carotid access in 4 out of the 5 patients in whom BGT was attempted. Successful recanalization (modified treatment in cerebral ischemia 2b-3) was obtained in all cases with no complications. CONCLUSIONS: Balloon Gliding Technique (BGT) is a safe technique that can safely overcome challenging anatomy during endovascular treatment of acute ischemic stroke. Further studies can assist in demonstrating both its safety and effectiveness.

Robotics for neuroendovascular intervention: Background and primer.

The simultaneous growth of robotic-assisted surgery and telemedicine in recent years has only been accelerated by the recent coronavirus disease 2019 pandemic. Robotic assistance for neurovascular intervention has garnered significant interest due to opportunities for tele-stroke models of care for remote underserved areas. Lessons learned from medical robots in interventional cardiology and neurosurgery have contributed to incremental but vital advances in medical robotics despite important limitations. In this article, we discuss robot types and their clinical justification and ethics, as well as a general overview on available robots in thoracic/abdominal surgery, neurosurgery, and cardiac electrophysiology. We conclude with current clinical research in neuroendovascular intervention and a perspective on future directions.

State of the Art: Venous Causes of Pulsatile Tinnitus and Diagnostic Considerations Guiding Endovascular Therapy.

Venous variants and pathologic abnormalities are the most common causes of pulsatile tinnitus. These conditions include causes of turbulence within normally located veins and sinuses, and abnormally enlarged or abnormally located veins in close transmissive proximity to the conductive auditory pathway. Such disorders include pathologic abnormalities of the lateral sinus (transverse sinus stenosis and sigmoid sinus wall anomalies), abnormalities and variants of the emissary veins, and anomalies of the jugular bulb and jugular vein. Despite being the most common causes for pulsatile tinnitus, venous variants and pathologic abnormalities are often overlooked in the workup of pulsatile tinnitus. Such oversights can result in delayed patient care and prolonged patient discomfort. Advances in both cerebrovascular imaging and endovascular techniques allow for improved diagnostic accuracy and an increasing range of endovascular therapeutic options to address pulsatile tinnitus. This review illustrates the venous causes of pulsatile tinnitus and demonstrates the associated endovascular treatment. © RSNA, 2021.

Early-Stage Radiology Volume Effects and Considerations with the Coronavirus Disease 2019 (COVID-19) Pandemic: Adaptations, Risks, and Lessons Learned.

OBJECTIVE: The coronavirus disease 2019 (COVID-19) pandemic resulted in significant loss of radiologic volume as a result of shelter-at-home mandates and delay of non-time-sensitive imaging studies to preserve capacity for the pandemic. We analyze the volume-related impact of the COVID-19 pandemic on six academic medical systems (AMSs), three in high COVID-19 surge (high-surge) and three in low COVID-19 surge (low-surge) regions, and a large national private practice coalition. We sought to assess adaptations, risks of actions, and lessons learned. METHODS: Percent change of 2020 volume per week was compared with the corresponding 2019 volume calculated for each of the 14 imaging modalities and overall total, outpatient, emergency, and inpatient studies in high-surge AMSs and low-surge AMSs and the practice coalition. RESULTS: Steep examination volume drops occurred during week 11, with slow recovery starting week 17. The lowest total AMS volume drop was 40% compared with the same period the previous year, and the largest was 70%. The greatest decreases were seen with screening mammography and dual-energy x-ray absorptiometry scans, and the smallest decreases were seen with PET/CT, x-ray, and interventional radiology. Inpatient volume was least impacted compared with outpatient or emergency imaging. CONCLUSION: Large percentage drops in volume were seen from weeks 11 through 17, were seen with screening studies, and were larger for the high-surge AMSs than for the low-surge AMSs. The lowest drops in volume were seen with modalities in which delays in imaging had greater perceived adverse consequences.

Coil migration during or after endovascular coiling of cerebral aneurysms.

BACKGROUND: Coil migration is a complication of endovascular coiling of cerebral aneurysms that has not been well studied. OBJECTIVE: To report the frequency, risk factors, management strategies, and outcomes of coil migration. METHODS: This was a retrospective analysis of the clinical and radiological data of patients who underwent cerebral aneurysm coiling complicated by coil migration at five neuroendovascular centers in the United States, Canada, and France between 2008 and 2018. RESULTS: Eighteen cases of coil migration met our study criteria with an occurrence of 0.3% (18/6071 cases) (procedural migration: 55%, delayed migration: 45%). The mean aneurysm maximal diameter, neck, and height to neck ratio in migration cases were 3.4±1.4 mm (range 2-7.6 mm), 2.4±0.9 mm (range 1.2-4.4 mm), and 1.4±0.4 (range 1-2.15), respectively. The 2 mm diameter coil was the most common (39%, range 1-2.5 mm) migrated coil. The length of the migrated coil was ≤4 cm in 95% of cases.Patients managed conservatively (5/18, 28%) did well. Thromboembolic and/or hemorrhagic complications were noted in 6/10 migration patients treated by endovascular modalities and in all migration patients who underwent surgical treatment (4/4). Three deaths occurred (3/18, 17%) related to high Hunt and Hess grade subarachnoid hemorrhage. CONCLUSION: Coil migration is an uncommon but important complication of cerebral aneurysm coiling. Small aneurysms, aspect ratio <1.6, and small coils are significant risk factors. Endovascular treatment, such as using a stent retriever, can be considered for procedural, proximal migration, and/or in cases of vessel occlusion. Delayed or distal migration should be managed conservatively.

Inadvertent Stent Retriever Detachment: A Multicenter Case Series and Review of Device Experience FDA Reports.

Mechanical thrombectomy using retrievable stents or stent retriever devices has become the mainstay of intra-arterial therapy for acute ischemic stroke. The recent publication of a series of positive trials supporting intra-arterial therapy as standard of care for the treatment of large vessel occlusion will likely further increase stent retriever use. Rarely, premature stent detachment during thrombectomy may be encountered. In our multicenter case series, we found a rate of detachment of less than 1% (n = 7/1,067), and all were first-generation Solitaire FR devices. A review of the US Food and Drug Administration database of device experience yielded 90 individual adverse reports of detachment. There were 82, 1 and 7 detachments of Solitaire FR (first generation), Solitaire FR2 (second generation) and Trevo devices, respectively. We conclude with a brief overview of the technical and procedural considerations which may be helpful in avoiding this rare complication.

Normal saline as a natural intravascular contrast agent for dynamic perfusion-weighted MRI of the brain: Proof of concept at 1.5T.

PURPOSE: Gadolinium-based contrast agents have associated risks. Normal saline (NS) is a nontoxic sodium chloride water solution that can significantly increase the magnetic resonance imaging (MRI) relaxation times of blood via transient hemodilution (THD). The purpose of this pilot study was to test in vivo in the head the potential of normal saline as a safer, exogenous perfusion contrast agent. MATERIALS AND METHODS: This Health Insurance Portability and Accountability Act (HIPAA)-compliant prospective study was approved by the local Institutional Review Board (IRB): 12 patients were scanned with T1 -weighted inversion recovery turbo spin echo pulse sequence at 1.5T. The dynamic inversion recovery pulse sequence was run before, during, and after the NS injection for up to 5 minutes: 100 ml of NS was power-injected via antecubital veins at 3-4 ml/s. Images were processed to map maximum enhancement area-under-the-curve, time-to-peak, and mean-transit-time. These maps were used to identify the areas showing significant NS injection-related signal and to generate enhancement time curves. Hardware and pulse sequence stability were studied via phantom experimentation. Main features of the time curves were tested against theoretical modeling of THD signal effects using inversion recovery pulse sequences. Pearson correlation coefficient (R) mapping was used to differentiate genuine THD effects from motion confounders and noise. RESULTS: The scans of 8 out of 12 patients showed NS injection-related effects that correlate in magnitude with tissue type (gray matter ∼15% and white matter ∼3%). Motion artifacts prevented ascertaining NS signal effects in the remaining four patients. Positive and negative time curves were observed in vivo and this dual THD signal polarity was also observed in the theoretical simulations. R-histograms that were approximately constant in the range 0.1 < |R| < 0.8 and leading to correlation fractions of Fcorr (|R| > 0.5) = 0.45 and 0.59 were found to represent scans with genuine THD signal effects. CONCLUSION: A measurable perfusion effect in brain tissue was demonstrated in vivo using NS as an injectable intravascular contrast agent. J. Magn. Reson. Imaging 2016;44:1580-1591.

Expanding Endovascular Therapy of Very Small Ruptured Aneurysms with the 1.5-mm Coil.

BACKGROUND: Very small ruptured aneurysms (≤3 mm) demonstrate a significant risk for procedural rupture with endovascular therapy. Since 2007, 1.5-mm-diameter coils have been available (Micrus, Microvention, and ev3), allowing neurointerventionalists the opportunity to offer patients with very small aneurysms endovascular treatment. In this study, we review the clinical and angiographic outcome of patients with very small ruptured aneurysms treated with the 1.5-mm coil. METHODS: This is a retrospective cohort study in which we examined consecutive ruptured very small aneurysms treated with coil embolization at a single institution. The longest linear aneurysm was recorded, even if the first coil was sized to a smaller transverse diameter. Very small aneurysms were defined as ≤3 mm. Descriptive results are presented. RESULTS: From July 2007 to March 2015, 81 aneurysms were treated acutely with coils in 78 patients presenting with subarachnoid hemorrhage. There were 5 patients with 3-mm aneurysms, of which the transverse diameter was ≤2 mm in 3 patients. In all 5 patients, a balloon was placed for hemostatic prophylaxis in case of rupture, and a single 1.5-mm coil was inserted for aneurysm treatment without complication. Complete aneurysm occlusion was achieved in 1 patient, residual neck in 2, and residual aneurysm in 2 patients. Aneurysm recanalization was present in 2 patients with an anterior communicating artery aneurysm; a recoiling attempt was unsuccessful in 1 of these 2 patients due to inadvertent displacement and distal coil embolization, but subsequent surgical clipping was successful. Another patient was retreated by surgical clipping for a residual wide-neck carotid terminus aneurysm. One patient died of ventriculitis 3 weeks after presentation; all 4 other patients had an excellent outcome with no rebleed at follow-up (mean 21 months, range 1-62). CONCLUSION: The advent of the 1.5-mm coil may be used in the endovascular treatment of patients with very small ruptured aneurysms, providing a temporary protection to the site of rupture in the acute phase. If necessary, bridging with elective clipping may provide definitive aneurysm treatment.

Duplication of the Posterior Cerebral Artery and the 'True Fetal' Variant.

We present a rare case of bilateral posterior cerebral artery variant anatomy seen in a patient presenting with acute ischemic stroke. An embryological explanation of the variant configuration is discussed along with demonstrative radiologic images and a display of the vascular territory supplied.

A guide to the external review of an academic radiology department.

External reviews are used to evaluate a department on a routine basis or prior to reappointment or recruitment of a department chair. The Society of Chairs of Academic Radiology Departments (SCARD) developed a template that outlines important components of an external review report and a table that outlines the objective information that can be requested from the institution/department prior to the reviewer's site visit. The template is meant to facilitate a high-quality review and serve as a guide to a chair who is preparing for his/her first review, chairs who serve as external consultants, and institutional officials seeking review of a radiology department.

Balloon guide catheter improves revascularization and clinical outcomes with the Solitaire device: analysis of the North American Solitaire Acute Stroke Registry.

BACKGROUND AND PURPOSE: Efficient and timely recanalization is an important goal in acute stroke endovascular therapy. Several studies demonstrated improved recanalization and clinical outcomes with the stent retriever devices compared with the Merci device. The goal of this study was to evaluate the role of the balloon guide catheter (BGC) and recanalization success in a substudy of the North American Solitaire Acute Stroke (NASA) registry. METHODS: The investigator-initiated NASA registry recruited 24 clinical sites within North America to submit demographic, clinical, site-adjudicated angiographic, and clinical outcome data on consecutive patients treated with the Solitaire Flow Restoration device. BGC use was at the discretion of the treating physicians. RESULTS: There were 354 patients included in the NASA registry. BGC data were reported in 338 of 354 patients in this subanalysis, of which 149 (44%) had placement of a BGC. Mean age was 67.3±15.2 years, and median National Institutes of Health Stroke Scale score was 18. Patients with BGC had more hypertension (82.4% versus 72.5%; P=0.05), atrial fibrillation (50.3% versus 32.8%; P=0.001), and were more commonly administered tissue plasminogen activator (51.6% versus 38.8%; P=0.02) compared with patients without BGC. Time from symptom onset to groin puncture and number of passes were similar between the 2 groups. Procedure time was shorter in patients with BGC (120±28.5 versus 161±35.6 minutes; P=0.02), and less adjunctive therapy was used in patients with BGC (20% versus 28.6%; P=0.05). Thrombolysis in cerebral infarction 3 reperfusion scores were higher in patients with BGC (53.7% versus 32.5%; P<0.001). Distal emboli and emboli in new territory were similar between the 2 groups. Discharge National Institutes of Health Stroke Scale score (mean, 12±14.5 versus 17.5±16; P=0.002) and good clinical outcome at 3 months were superior in patients with BGC compared with patients without (51.6% versus 35.8%; P=0.02). Multivariate analysis demonstrated that the use of BGC was an independent predictor of good clinical outcome (odds ratio, 2.5; 95% confidence interval, 1.2-4.9). CONCLUSIONS: Use of a BGC with the Solitaire Flow Restoration device resulted in superior revascularization results, faster procedure times, decreased need for adjunctive therapy, and improved clinical outcome.

Age-related relaxo-volumetric quantitative magnetic resonance imaging of the major salivary glands.

OBJECTIVE: To study age-related characteristics of T1 and T2 relaxation times and volume of the major salivary glands. METHODS: Thirty-five subjects (0.5-87 years old) with normal salivary glands were imaged with mixed turbo spin-echo pulse sequences at 1.5-T magnetic resonance units. Bilateral parotid, submandibular, and sublingual glands were segmented manually. Histograms for each salivary gland were generated and modeled with Gaussian functions for every parameter. RESULTS: Seventy parotid glands, 52 submandibular glands, and 50 sublingual glands were segmented and the histograms were analyzed. The parotid gland exhibited shorter-peak T1s and longer-peak T2s relative to the submandibular and sublingual glands. The peak T2s for all glands showed a minimum value between 2 and 4 years of age and increased monotonically thereafter. From birth to early adulthood, all glands increased in size logarithmically. CONCLUSION: Age-related relaxo-volumetric changes of the major salivary glands show clear T2 and volumetric age-related patterns for all glands.

The safety of anticoagulation in patients with intracranial aneurysms.

BACKGROUND AND PURPOSE: Little is known about the safety of long-term anticoagulation in patients with unruptured saccular intracranial aneurysms, although case reports of anticoagulation in patients with fusiform and saccular aneurysms have been published. The goal of this study was to estimate the rate of subarachnoid hemorrhage (SAH) due to aneurysm rupture in patients with intracranial saccular aneurysms receiving therapeutic doses of anticoagulation. METHODS: This was a retrospective case series of patients with intradural aneurysms receiving therapeutic doses of anticoagulation (defined as a dose that achieves a target INR >2.0 or the equivalent dose of another anticoagulant). The primary outcome was SAH due to aneurysm rupture while receiving anticoagulation treatment. The rate of SAH due to aneurysm rupture was calculated among patients with aneurysms documented on imaging. RESULTS: 42 patients with 48 intradural aneurysms on anticoagulation were identified. Their mean age was 67 years (range 40-83) and 28 (67%) were women. The mean aneurysm size was 5.1±3.6 mm and 40 (83%) aneurysms were in the anterior circulation. The mean±SD follow-up was 495±749 days per patient. Twelve patients had their aneurysms coiled, clipped or surgically wrapped before the period of anticoagulation. Three patients had clipping or coiling of their aneurysms during the period of anticoagulation. Six patients had a history of aneurysm rupture prior to anticoagulation, of which two were treated by coiling and four by clipping. Among the 48 aneurysms, 32 were never coiled or clipped prior to anticoagulation. No anticoagulated patients with known aneurysms developed SAH during 57 patient-years of follow-up. The patients with untreated aneurysms had 31 patient-years of follow-up and those who underwent clipping, coiling or surgical wrapping of their aneurysms had 26 patient-years of follow-up while receiving anticoagulation (for a combined total of 57 years of follow up). CONCLUSIONS: The risk of aneurysm rupture is not increased in patients receiving systemic anticoagulation. However, these results should be interpreted with caution given the small sample size in this study and the need for a prospective study to confirm these findings.

Quantitative evaluation of light scattering intensities of the crystalline lens for radiation related minimal change in interventional radiologists: a cross-sectional pilot study.

To evaluate low-dose X-ray radiation effects on the eye by measuring the amount of light scattering in specific regions of the lens, we compared exposed subjects (interventional radiologists) with unexposed subjects (employees of medical service companies), as a pilot study. According to numerous exclusionary rules, subjects with confounding variables contributing to cataract formation were excluded. Left eye examinations were performed on 68 exposed subjects and 171 unexposed subjects. The eye examinations consisted of an initial screening examination, followed by Scheimpflug imaging of the lens using an anterior eye segment analysis system. The subjects were assessed for the quantity of light scattering intensities found in each of the six layers of the lens. Multiple stepwise regression analyses were performed with the stepwise regression for six variables: age, radiation exposure, smoking, drinking, wearing glasses and workplace. In addition, an age-matched comparison between exposed and unexposed subjects was performed. Minimal increased light scattering intensity in the posterior subcapsular region showed statistical significance. Our results indicate that occupational radiation exposure in interventional radiologists may affect the posterior subcapsular region of the lens. Since by its very nature this retrospective study had many limitations, further well-designed studies concerning minimal radiation-related lens changes should be carried out in a low-dose exposure group.

Comparison of topogram-based body size indices for CT dose consideration and scan protocol optimization.

PURPOSE: To retrospectively compare different topogram-based patient body size indices and to determine the optimal topogram-based body size index as a basis for body computed tomography (CT) dose consideration and scan protocol optimization. METHODS: Forty-three routine thorax and abdomen CT scans are studied retrospectively, with patient ages ranging from 18 to 67 yr. The individual patient's water-equivalent diameter (D(w)) of the scanned body region is computed from CT DICOM images as the "gold standard," after first converting from Hounsfield units values to µa values, where µ is the normalized tissue attenuation coefficient and a is the area per pixel. Four topogram-based body size indices [average diameter (D), girth (G), topogram projection area (E(topo)), and improved topogram projection area (E(topo)('))] are computed and correlated with D(w) using linear regression analysis. Specifically, D is calculated by averaging the coronal and sagittal diameters; G is computed by modeling the patient's cross-section as an ellipse; E(topo) is the product of the mean topogram pixel value and the width of the scanned body region; and (E(topo)(')) incorporates E(topo) with correction of patient miscentering and water attenuation coefficient. The accuracy of these four approaches for estimation of D(w) is assessed using linear regression models. Results are given in terms of 95% confidence intervals (CIs). RESULTS: Regression analysis results in four different linear models. The standard error (95% CI) for estimation of D(w) from D and G was ±2.8 and ±3.1 cm, respectively (p = 0.297). The standard error for estimation of D(w) from E(topo) was significantly less than that from D (±2.1 cm, p < 0.01). The standard error for estimation of D(w) from (E(topo)(')) was ±1.3 cm, significantly less than that from E(topo) (p < 0.01). CONCLUSIONS: Among the four topogram-based patient body indices, (E(topo)(')) is the most accurate for estimation of individual x-ray attenuation of the scanned body region. Thus, (E(topo)(')) is an optimal topogram-based patient body size index that is relevant for determining the proper CT dose level for individual patients.

Intra-arterial treatment methods in acute stroke therapy.

Acute revascularization is associated with improved outcomes in ischemic stroke patients. It is unclear which method of intra-arterial intervention, if any, is ideal. Promising approaches in acute stroke treatment are likely a combination of intravenous and endovascular revascularization efforts, combining early treatment initiation with direct clot manipulation and/or PTA/stenting. In this review, we will discuss available thrombolytic therapies and endovascular recanalization techniques, beginning with chemical thrombolytic agents, followed by mechanical devices, and a review of ongoing trials. Further randomized studies comparing medical therapy, intravenous and endovascular treatments are essential, and their implementation will require the wide support and enthusiasm from the neurologic, neuroradiologic, and neurosurgical stroke communities.

Balloon angioplasty for intracranial atherosclerotic disease: periprocedural risks and short-term outcomes in a multicenter study.

BACKGROUND AND PURPOSE: whether stenting is superior to angioplasty in the treatment of intracranial atherosclerotic disease is unknown. Dissections, vessel rupture, and lesion recoil observed with primary angioplasty using balloon catheters designed for coronary arteries have undermined the role of primary angioplasty as a preferred treatment for intracranial atherosclerotic disease. The goal of this study is to report the immediate and 3-month outcomes of treating patients with intracranial atherosclerotic disease with angioplasty balloon catheters in a multicenter study. METHODS: this is a retrospective review of 74 patients from 4 institutions treated with primary angioplasty for intracranial atherosclerotic disease over a 6-year time period. Technical success (residual stenosis ≤ 50%), periprocedural success (no vascular complication within 72 hours), and 3-month outcomes are reported. RESULTS: the mean degree of stenosis pretreatment was 79% ± 14% and reduced to 34% ± 18% after angioplasty. Technical success was achieved in 68 (92%; 95% CI, 83% to 97%) of the 74 patients. Periprocedural success was achieved in 65 (88%; 95% CI, 78% to 94%) of the 74 patients. There were 4 (5%; 95% CI, 1.5% to 13%) major procedure-related strokes, 2 of which resulted in death within 6 hours of the procedure. The 30-day stroke/death rate was 5% (4 of 74; CI, 1.5% to 13%). Three-month follow-up was available in 71 patients. In this interval, 2 patients had new stroke, 1 in the ipsilateral territory and the other in the contralateral territory. The 3-month stroke or death rate was 8.5% (6 of 71; CI, 3.1% to 17.5%); the retreatment rate was 2.8% (2 of 71; CI, 0.3% to 10%). CONCLUSIONS: balloon angioplasty is a relatively safe alternative treatment for intracranial atherosclerotic disease. Its role in the long-term secondary prevention of recurrent stroke as compared with intracranial stenting and medical therapy remains to be determined, preferably in a randomized study.