Imramsjah M. J. van der Bom

Endovascular treatment of tandem vascular occlusions in acute ischemic stroke.

Background and purpose Tandem vascular occlusions are an important cause of acute ischemic stroke (AIS) and present unique treatment challenges. We report our experience of managing a subset of AIS patients with extracranial vascular stenting/angioplasty and intracranial revascularization. Methods Consecutive patients who presented at three centers with AIS from tandem vascular occlusions confirmed by brain and neck CT imaging were included in the study. We retrospectively analyzed the patient demographics, National Institute of Health Stroke Scale (NIHSS) score and modified Rankin Scale (mRS) score at the time of admission, treatment strategy, angiographic results using the Thrombolysis In Cerebral Infarction (TICI) score, and clinical and imaging follow-up. Results Twenty-eight patients were included. The mean NIHSS score at admission was 18. Extracranial carotid occlusions with a concomitant middle cerebral artery occlusion were seen in 89.3% of patients (n=25) and vertebral artery combined with basilar artery lesions in 10.7% (n=3). An antegrade approach (ie, treatment of the extracranial lesion first) was used in 24 patients (85.7%). Proximal occlusion recanalization was achieved usually with a stent (n=27; 96.4%). Pursuant to intracranial revascularization techniques, ≥TICI 2A recanalization was seen in 96.4% of patients. An mRS score of ≤2 at 90 days was achieved in 56.5% of patients. Conclusions Our study shows preliminary data from three centers on recanalization of tandem occlusions in patients presenting with AIS. There was a preference to revascularize the proximal occlusion using a stent followed by distal recanalization with mechanical thrombectomy, intra-arterial thrombolysis or a combination of these. This approach has low periprocedural complications and can achieve an excellent angiographic and clinical outcome.

Quantitative analysis of high-resolution, contrast-enhanced, cone-beam CT for the detection of intracranial in-stent hyperplasia

Background Intracranial in-stent hyperplasia is a stroke-associated complication that requires routine surveillance. Objective To compare the results of in vivo experiments to determine the accuracy and precision of in-stent hyperplasia measurements obtained with modified C-arm contrast-enhanced, cone-beam CT (CE-CBCT) imaging with those obtained by ‘gold standard’ histomorphometry. Additionally, to carry out clinical analyses comparing this CE-CBCT protocol with digital subtraction angiography (DSA). Methods A non-binned CE-CBCT protocol (VasoCT) was used that acquires x-ray images with a small field-of-view and applies a full-scale reconstruction algorithm providing high-resolution three-dimensional (3D) imaging with 100 µm isotropic voxels. In an vivo porcine model, VasoCT cross-sectional area measurements were compared with gold standard vessel histology. VasoCT and DSA were used to calculate in-stent stenosis in 23 imaging studies. Results Porcine VasoCT cross-sectional stent, lumen, and in-stent hyperplasia areas strongly correlated with histological measurements (r2=0.97, 0.93, 0.90; slope=1.14, 1.07, and 0.76, respectively; p<0.0001). Clinical VasoCT percentage stenosis correlated well with DSA percentage stenosis (r2=0.84; slope=0.76), and the two techniques were free of consistent bias (Bland–Altman, bias=3.29%; 95% CI −14.75% to 21.33%). An illustrative clinical case demonstrated the advantages of VasoCT, including 3D capability and non-invasive IV contrast administration, for detection of in-stent hyperplasia. Conclusions C-arm VasoCT is a high-resolution 3D capable imaging technique that has been validated in an animal model for measurement of in-stent tissue growth. Successful clinical implementation of the protocol was performed in a small case series.

Chemical exchange saturation transfer effect in blood

In this report, the feasibility of using blood as an agent for Chemical Exchange Saturation Transfer (CEST) effect is investigated.

Frameless multimodal image guidance of localized convection-enhanced delivery of therapeutics in the brain

Introduction Convection-enhanced delivery (CED) has been shown to be an effective method of administering macromolecular compounds into the brain that are unable to cross the blood-brain barrier. Because the administration is highly localized, accurate cannula placement by minimally invasive surgery is an important requisite. This paper reports on the use of an angiographic c-arm system which enables truly frameless multimodal image guidance during CED surgery. Methods A microcannula was placed into the striatum of five sheep under real-time fluoroscopic guidance using imaging data previously acquired by cone beam computed tomography (CBCT) and MRI, enabling three-dimensional navigation. After introduction of the cannula, high resolution CBCT was performed and registered with MRI to confirm the position of the cannula tip and to make adjustments as necessary. Adeno-associated viral vector-10, designed to deliver small-hairpin micro RNA (shRNAmir), was mixed with 2.0 mM gadolinium (Gd) and infused at a rate of 3 μl/min for a total of 100 μl. Upon completion, the animals were transferred to an MR scanner to assess the approximate distribution by measuring the volume of spread of Gd. Results The cannula was successfully introduced under multimodal image guidance. High resolution CBCT enabled validation of the cannula position and Gd-enhanced MRI after CED confirmed localized administration of the therapy. Conclusion A microcannula for CED was introduced into the striatum of five sheep under multimodal image guidance. The non-alloy 300 μm diameter cannula tip was well visualized using CBCT, enabling confirmation of the position of the end of the tip in the area of interest.

Feasibility of a Modified Cone-Beam CT Rotation Trajectory to Improve Liver Periphery Visualization during Transarterial Chemoembolization

PURPOSE To compare liver coverage and tumor detectability by using preprocedural magnetic resonance (MR) images as a reference, as well as radiation exposure of cone-beam computed tomography (CT) with different rotational trajectories. MATERIALS AND METHODS Fifteen patients (nine men and six women; mean age ± standard deviation, 65 years ± 5) with primary or secondary liver cancer were retrospectively included in this institutional review board-approved study. A modified cone-beam CT protocol was used in which the C-arm rotates from +55° to -185° (open arc cone-beam CT) instead of -120° to +120° (closed arc cone-beam CT). Each patient underwent two sessions of transarterial chemoembolization between February 2013 and March 2014 with closed arc and open arc cone-beam CT (during the first and second transarterial chemoembolization sessions, respectively, as part of the institutional transarterial chemoembolization protocol). For each cone-beam CT examination, liver volume and tumor detectability were assessed by using MR images as the reference. Radiation exposure was compared by means of a phantom study. For statistical analysis, paired t tests and a Wilcoxon signed rank test were performed. RESULTS Mean liver volume imaged was 1695 cm(3) ± 542 and 1857 cm(3) ± 571 at closed arc and open arc cone-beam CT, respectively. The coverage of open arc cone-beam CT was significantly higher compared with closed arc cone-beam CT (97% vs 86% of the MR imaging liver volume, P = .002). In eight patients (53%), tumors were partially or completely outside the closed arc cone-beam CT field of view. All tumors were within the open arc cone-beam CT field of view. The open arc cone-beam CT radiation exposure by means of weighted CT index was slightly lower compared with that of closed arc cone-beam CT (-5.1%). CONCLUSION Open arc cone-beam CT allowed for a significantly improved intraprocedural depiction of peripheral hepatic tumors while achieving a slight radiation exposure reduction.

Target delineation for radiosurgery of a small brain arteriovenous malformation using high-resolution contrast-enhanced cone beam CT

Three years following endovascular embolization of a 3 mm ruptured arteriovenous malformation (AVM) of the left superior colliculus in a 42-year-old man, digital subtraction angiography showed continuous regrowth of the lesion. Thin-slice MRI acquired for treatment planning did not show the AVM nidus. The patient was brought back to the angiography suite for high-resolution contrast-enhanced cone beam CT (VasoCT) acquired using an angiographic c-arm system. The lesion and nidus were visualized with VasoCT. MRI, CT and VasoCT data were transferred to radiation planning software and mutually co-registered. The nidus was annotated for radiation on VasoCT data by an experienced neurointerventional radiologist and a dose/treatment plan was completed. Due to image registration, the treatment area could be directly adopted into the MRI and CT data. The AVM was completely obliterated 10 months following completion of the radiosurgery treatment.

Advances in Stroke Advances in Interventional Neuroradiology

Carotid artery stenting (CAS) has not been shown to be as safe as carotid endarterectomy for treatment of symptomatic extracranial carotid artery stenosis in the immediate postoperative period. However, beyond the postoperative period, data continues to support a role for CAS in selected patients. A large systematic review of 206 individual studies (54 713 total patients) undergoing CAS found the cumulative 30-day risk of stroke or death to be 7.6% in symptomatic and 3.3% in asymptomatic patients.1 Factors associated with increased risk of adverse outcomes in both groups were age 75 years (relative risk [RR] 1.88), hypertension (RR 1.86), and coronary artery disease (RR 1.41). Use of embolic protection devices significantly reduced the risk of stroke or death (RR 0.57). Although reports of adverse events vary widely in the literature, there has been a trend toward overall reduction in risk over the past several years, suggesting that use of embolic protection devices, careful patient selection, and increasing operator experience may be important factors in minimizing risk. The vast majority of these data (97%) are outside the standards of a randomized controlled trial (RCT), emphasizing the need for data from the trials that are currently enrolling patients. Among the larger studies currently enrolling patients are the Carotid Stenting for High Risk Surgical Patients (CHOICE, Abbott Vascular, target 5000 patients), Asymptomatic Carotid Surgery Trial-2 (ACST-2, target 5000 patients), and Stent-Protected Angioplasty in Asymptomatic Carotid Artery Stenosis versus Endarterectomy trial (SPACE-2, target 3640 patients). This year, we received our first update from the Carotid Revascularization Endarterectomy versus Stenting Trial (CREST), the largest RCT to date comparing the periprocedural safety and long-term (4 years) efficacy of CAS versus carotid endarterectomy.2 Data from the lead-in phase demonstrated an overall 30-day stroke and death rate of 4.4%. Restenosis rates in the lead-in phase were reported to be 13% with 1.2% of patients requiring repeat revascularization by 1-year follow-up. These numbers compare to restenosis rates of 10.7% and 4.6% in patients undergoing CAS and carotid endarterectomy, respectively, in the SPACE trial3 and 19% of CAS patients in the Stenting and Angioplasty with Protection in Patients at High Risk of Endarterectomy (SAPPHIRE) study. 4 The Carotid Revascularization Using Endarterectomy

Dantrolene for cerebral vasospasm after subarachnoid haemorrhage: a randomised double blind placebo-controlled safety trial

Background Dantrolene is neuroprotective in animal models and may attenuate cerebral vasospasm (cVSP) in human aneurysmal subarachnoid haemorrhage (aSAH). We evaluated safety, feasibility and tolerability of intravenous dantrolene (IV-D) in patients with aSAH. Methods In this single-centre, randomised, double blind, placebo-controlled trial, 31 patients with aSAH were randomised to IV-D 1.25 mg every 6 h for 7 days (n=16) or equiosmolar free water/5% mannitol (placebo; n=15). Primary safety end points were incidence of hyponatraemia (sNa≤132 mmol/L) and liver toxicity (proportion of patients alanine transaminase, aspartate aminotransferase and AlkPhos >5× upper-limit-of-normal). Secondary end points included tolerability, systemic hypotension and intracranial hypertension. Efficacy was explored for clinical/radiological cVSP, delayed cerebral ischaemia (DCI), and 3-month functional outcomes. Quantitative analyses of angiograms and daily transcranial Doppler (TCD) were performed. Results Between IV-D versus placebo, no differences were observed in the primary outcomes (hyponatremia 44% vs 67% (p=0.29); liver toxicity 6% vs 0% (p=1.0)). Three patients in the IV-D versus two in the placebo group had severe adverse events possibly attributable to infusion and reached stop criteria: one IV-D patient developed liver toxicity; two patients in each group developed brain oedema requiring osmotherapy. The majority of adverse events were not related to infusion (17 vs 5 (RR 2.2; 95% CI 0.7 to 6.7; p=0.16) in IV-D vs placebo). No differences in any categorical cVSP outcomes, DCI, 3-month outcomes or quantitative angiogram and TCD analyses were seen in this small safety trial not powered to detect efficacy. Conclusions In this small trial, IV-D after aSAH was feasible, tolerable and safe. Trial registration number http://clinicaltrials.gov NCT01024972.

Radiation dose reduction utilizing noise reduction technology during uterine artery embolization: a pilot study.

OBJECTIVE To assess the radiation dose reduction during uterine artery embolization utilizing dose reduction technology. METHODS A total of 58 women underwent uterine artery embolization. A total of 26 procedures were performed in a standard fluoroscopy suite; 32 procedures were performed utilizing a novel imaging platform. Radiation dose data and acquisition parameters were compared. RESULTS The new platform provided significant reduction in the median radiation dose (P<.001): from 389Gy cm(2) to 145Gy cm(2). There were no differences between the groups with regard to acquisition parameters. CONCLUSION The new imaging platform provided a 61% dose reduction during uterine artery embolization without a significant change in acquisition parameters.

Quantitative In Vivo Evaluation of Neointimal Hyperplasia Using High-Resolution Contrast-Enhanced Cone-Beam Computed Tomography

Intracranial atherosclerotic disease (ICAD) is the most common cause of stroke throughout the world. Patients with severe arterial stenosis and a recent stroke or transient ischemic attack are at high risk of recurring stroke. In an attempt to improve the clinical outcome of patients with severe, symptomatic ICAD, percutaneous transluminal angioplasty and intracranial stenting have become treatment options over the last years. Follow-up imaging of patients with ICAD that underwent intracranial stenting is generally done using 2D digitally subtracted angiography. Since often the vessel path is curved and the neointimal hyperplasia (NH) is eccentric, in-stent restenosis (ISR) may be under- or overestimated using 2D techniques.Copyright