4D-DSA for Assessment of the Angioarchitecture and Grading of Cranial Dural AVF.

BACKGROUND AND PURPOSE: Time-resolved 3D rotational angiography (4D-DSA) has been used to demonstrate details of the angioarchitecture of AVM, whereas it has rarely been used to describe features of dural AVF. In this exploratory study, we analyzed dural AVFs with a novel 4D software prototype, developed and provided by Siemens, to determine whether identification of the location of the fistulous point, grading, and treatment planning were feasible. MATERIALS AND METHODS: 4D-DSA volumes were calculated from existing 3D rotational angiography data sets of patients with dural AVFs. The 4D-DSA volumes were displayed in a virtual DSA mode and MPR or MIP in 3 orthogonal planes and compared with 2D-DSA by 2 experienced neuroradiologists. Fusions with unenhanced CT or MR images were used to improve visualization of adjacent anatomic structures. RESULTS: Comparison with 2D-DSA showed that evaluation of the fistulous point and grading according to the classification of Borden, Cognard, or Barrow was feasible in 26 of 27 cases. In 8 of 27 cases, 4D-DSA was considered advantageous for determining the fistulous point and the course of the draining vein in the dural AVF with cortical venous drainage, especially in the frontoethmoidal and frontoparietal regions. In 6 cases, the display of angioarchitecture was considered inferior to that of 2D-DSA due to motion artifacts, suboptimal selection of the injected vessel, and lack of temporal resolution. CONCLUSIONS: Detailed analysis of dural AVFs according to the standardized display of 4D-DSA volumes was feasible and helpful in understanding the angioarchitecture in selected cases. Further improvement and validation of the 4D software should solidify the complementary role of 4D-DSA to conventional 2D-DSA series.

4D Flat Panel Conebeam CTA for Analysis of the Angioarchitecture of Cerebral AVMs with a Novel Software Prototype.

BACKGROUND AND PURPOSE: Time-resolved 3DRA (4D-DSA) and flat panel conebeam CTA are new methods for visualizing the microangioarchitecture of cerebral AVMs. We applied a 4D software prototype to a series of cases of AVMs to assess the utility of this method in relation to treatment planning. MATERIALS AND METHODS: In 33 patients with AVMs, 4D volumes and flat panel conebeam CTA images were recalculated from existing 3D rotational angiography data. The multiplanar reconstructions were used to determine intranidal arteriovenous branching patterns, categorize them according to common classifications of AVM angioarchitecture, and compare the results with those from 2D-DSA. RESULTS: 4D flat panel conebeam CTA showed angioarchitectural features equal to or better than those of 2D-DSA in 30 of 33 cases. In particular, the reconstructions helped in understanding the intranidal microvasculature. Fistulous direct arteriovenous connections with a low degree of arterial branching (n = 22) could be distinguished from plexiform arterial networks before the transition to draining veins (n = 11). We identified AVMs with a single draining vein (n = 20) or multiple draining veins (n = 10). Arteriovenous shunts in the lateral wall of the draining veins (n = 22) could be distinguished from cases with increased venous branching and shunts between corresponding intranidal arteries and veins (n = 11). Limitations were the time-consuming postprocessing and the difficulties in correctly tracing intranidal vessels in larger and complex AVMs. CONCLUSIONS: 4D flat panel conebeam CTA reconstructions allow detailed analysis of the nidal angioarchitecture of AVMs. However, further improvements in temporal resolution and automated reconstruction techniques are needed to use the method generally in clinical practice.

4D Flat Panel Conebeam CTA for In Vivo Imaging of the Microvasculature of the Human Cortex with a Novel Software Prototype.

It was the aim of our pilot study to investigate whether time-resolved flat panel conebeam CTA is able to demonstrate small cortical vessels in vivo. In 8 patients with small AVMs, time-resolved coronal MPRs of the vasculature of the frontal cortex were recalculated from 3D rotational angiography datasets with the use of a novel software prototype. 4D flat panel conebeam CTA demonstrated the course of the cortical arteries with small perpendicular side branches to the underlying cortex. Pial arterial and venous networks could also be identified, corresponding to findings in injection specimens. Reasonable image quality was achieved in 6 of 8 cases. In this small study, in vivo display of the cortical microvasculature with 4D flat panel conebeam CTA was feasible and superior to other angiographic imaging modalities.

Comparison of carotid and basilar bifurcation aneurysms versus non-T-angled bifurcations: the geometry is associated with the outcome.

Patients with ruptured aneurysms of carotid bifurcation artery seem to suffer less often from cerebral vasospasm and early brain injury and have a better clinical outcome. Aim of our study was to identify differences in clinical course and outcome in aneurysms of terminus segments (carotid bifurcation artery and basilar tip) compared to aneurysms of other aneurysm locations except carotid bifurcation artery and basilar tip. Patients with SAH were entered into a prospectively collected database (1999 to June 2014). A total of 471 patients ('T-shaped' aneurysms n = 63, 'non-T-shaped' aneurysms n = 408) were selected. Outcome was assessed by modified Rankin Scale (mRS) 6 months after SAH. Mean age was 53.75 years. Statistically, analysis showed a significant better outcome in 'T-shaped' aneurysms (p = 0.0001) and a significant lower mortality rate (p = 0.02) despite higher rates of Fisher 3 bleeding pattern and CVS. In 'T-shaped' aneurysms, no prognostic factors for outcome could be detected. In 'non-T-shaped' aneurysms admission status (p < 0.0001), early hydrocephalus (p < 0.0001), shunt-dependence (p = 0.001), and the occurrence of severe CVS (p = 0.01) statistically were factors influencing patients' outcome. Multivariate analysis showed 'non-T-shaped' aneurysms itself as independent prognostic factor for patients' outcome. Despite same rate of poor admission status, early hydrocephalus and shunt dependence 'T-shaped' aneurysms have a highly significantly better. Pathophysiological mechanism actually is not understood. Further studies are necessary to identify, which factors lead to the decreased outcome in "non-T-shaped"- aneurysms.

Efficacy of Mechanical Thrombectomy Using Stent Retriever and Balloon-Guiding Catheter.

PURPOSE: Intra-arterial therapy of acute ischemic stroke has developed rapidly in recent years. Due to proven efficacy in randomized trials, stent retrievers were replacing first-generation thrombectomy devices and have been defined as method of choice. However, aspiration catheters or a combination of several techniques have shown promising rates of successful recanalizations. To create a basis for comparison of the new approaches according to real-world data, we determined the first pass recanalization rate of an evidence-based standard technique with the use of a stent retriever in combination with a balloon-guiding catheter. The assessment was based on the number of required passages and reperfusion rate, but not on clinical results. METHODS: Patients from our institution with anterior circulation occlusions and mechanical thrombectomy by using stent retrievers in combination with balloon-guiding catheters were analyzed retrospectively. Reperfusion was graded with the "thrombolysis in cerebral infarction" (TICI) classification on post-interventional angiograms. Additionally, the number of passes and the duration of the recanalization procedure were recorded. RESULTS: Between 2014 and July 2017, 201 patients met the inclusion criteria. Successful recanalization, defined as a TICI scale 2b/3, was 91% (TICI 2b was achieved in 44% and TICI 3 in 47%) after the procedure. After the first passage, successful recanalization was achieved in 65% of the patients. Mean number of passes was 1.4 (1-5 passes) for all patients. Median duration of the procedure was 49 min (0:11-2:35 h). CONCLUSIONS: Even a standard thrombectomy technique with the use of a stent retriever together with a balloon-guiding catheter provides reasonable recanalization rates with only one passage. The results can be taken as benchmark for alternative and more complex techniques.

Safety and Efficacy of Aneurysm Treatment with the WEB: Results of the WEBCAST 2 Study.

BACKGROUND AND PURPOSE: Flow disruption with the Woven EndoBridge (WEB) device is an innovative technique for the endovascular treatment of wide-neck bifurcation aneurysms. The initial version of the device (WEB Double-Layer) was evaluated in the WEB Clinical Assessment of IntraSaccular Aneurysm Therapy (WEBCAST) study, whereas the French Observatory study evaluated both WEB Double-Layer and Single-Layer versions of the device. WEBCAST 2 was designed to evaluate the WEB Single-Layer with Enhanced Visualization. MATERIALS AND METHODS: Patients with wide-neck bifurcation aneurysms for which WEB treatment was possible were included. Clinical data including adverse events and clinical status at 1 month and 1 year were collected and analyzed. A core laboratory evaluated anatomic results at 1 year following the procedure. RESULTS: Ten European neurointerventional centers included 55 patients (38 women; 27-77 years of age; mean, 54.4 ± 10.0 years) with 55 aneurysms. Aneurysm locations were the middle cerebral artery in 25 aneurysms (45.5%), the anterior communicating artery in 16 (29.1%), the basilar artery in 9 (16.4%), and the internal carotid artery terminus in 5 (9.1%). Procedural morbidity and mortality at 1 month were, respectively, 1.8% (1/55 patients) and 0.0% (0/55 patients). Morbidity and mortality at 1 year were, respectively, 3.9% (2/51 patients) and 2.0% (1/51 patients). At 1 year, complete occlusion was observed in 27/50 aneurysms (54.0%); neck remnant, in 13/50 (26.0%); and aneurysm remnant, in 10/50 (20.0%) (adequate occlusion in 40/50, 80.0%). CONCLUSIONS: WEBCAST 2 confirms the high safety and efficacy of WEB aneurysm treatment demonstrated in the WEBCAST and French Observatory studies.

Time-resolved 3D Rotational Angiography (4D DSA) of the Lenticulostriate Arteries: Display of Normal Anatomic Variants and Collaterals in Cases with Chronic Obstruction of the MCA.

PURPOSE: The lenticulostriate arteries (LSA) and other perforators may play a role for collateral supply in cases with ischemia due to stenosis or occlusions of the middle cerebral artery (MCA). Purpose of this case series was to evaluate the potential of time-resolved 3D rotational angiography data sets (4D DSA) for detailed visualization of anatomic variants of LSA feeders and for display of local collaterals involving the LSA in cases with chronic MCA obstruction. METHODS: Multiplanar and volume rendering reconstructions of 4D DSA data were computed in addition to standard postprocessing in 24 patients who had indications for 3D rotational angiography (3DRA) of the internal carotid artery (ICA) without pathologies of the ICA, middle cerebral artery (MCA) and anterior cerebral artery (ACA) main stems (n = 18) or with stenosis or chronic occlusion of the MCA (n = 6). For acquisition of 3DRA, we used a modified digital subtraction angiography (DSA) image acquisition protocol with an extended rotation angle of 260° and a prolonged scan time of 12 s on a Siemens Axiom Artis Zee biplane neuroangiography equipment. The 4D reconstructions of existing 3DRA data were computed on a dedicated workstation. Origin and course of LSA and other perforators were analyzed according to coronal multiplanar reconstructions (MPRs) with slice thicknesses between 6 and 28 mm. RESULTS: In all cases 4D reconstructions of the LSA were technically feasible and evaluable. As expected, origin and course of LSA showed a wide range of variations: The most common pattern was a common trunk dividing into multiple ascending branches originating from the proximal M1 (n = 5) or the proximal A1 segment (n = 4). Alternatively, 8 patients showed several individual branches that directly originated from the proximal M1 segment of the MCA and occasionally from the A1 segment of the ACA. In patients with M1 stenosis or occlusion, 4 out of 6 cases had local collaterals with involvement of proximal LSA trunks and a network parallel to the obstructed vessel segment. The 4D reconstructions were found to be equivalent (n = 16) or superior to 3D reconstructions (n = 8). CONCLUSION: The 4D DSA reconstructions provide a reliable display of normal LSA variants and connections to local collateral networks in cases with chronic MCA obstruction. The possibility to select a correct angiographic phase is advantageous compared to 3D DSA.

Optimization of the Surgical Approach in AVMs Using MRI and 4D DSA Fusion Technique : A technical note.

PURPOSE: Previously published data demonstrated the possibility of displaying the angioarchitecture of intracranial vascular malformations using time-resolved 3D imaging (4D digital subtraction angiography [DSA]). The purpose of our study was to prove the technical feasibility of creating fused images of time-resolved 3D reconstructions and MPRAGE MRI data sets and to check the reliability of the correct anatomical display of the angioma nidus and the venous drainage in the fused images of patients with intracranial arteriovenous malformations (AVM). PATIENTS AND METHODS: In this study 20 patients with intracranial AVM underwent pretherapeutic DSA and time-resolved 3D DSA in addition to MRI including MPRAGE sequences. The images were post-processed with the fusion software tool on a dedicated research workstation. The fusion of both imaging modalities was done semi-automatically with automatic co-registration software followed by a manual co-registration. RESULTS: Co-registered DSA/MRI data sets of 20 untreated AVMs were evaluated independently by two reviewers. Image fusion was successful in all 20 cases with an acceptable additional set-up time. The fused images were highly scored by the two raters in respect to their congruency of the dedicated regions. Precise anatomical localization of the nidus, the feeding arteries and the draining veins were possible with the merged images. CONCLUSION: Creating fused images of time-resolved 3D DSA and contrast-enhanced T1-weighted MPRAGE MR images might be beneficial for the preoperative and intrasurgical workflow in patients with AVMs. This new software tool fulfils the required quality and accuracy of the merged images. The clinical validation has to be proven in further studies.

Decision-making in a patient with cardiac arrest due to venous thromboembolism within 24 h after glioblastoma resection.

In the fulminant VTE form with cardiac arrest, systemic thrombolysis remains the most effective therapy. However, several contraindications restrict the use such as intracranial neoplasm or a recent history of intracranial surgery. Here, we report the case of a 59-year-old man who underwent glioblastoma resection and suffered from a fulminant pulmonary embolism with cardiac arrest. After CPR, continuous tPA infusion via an endovascularly placed pulmonary catheter was maintained over a period of 8 h. In this case, we report on our decision-making process and the use of local thrombolysis as a successful therapy in a patient with multiple contraindications.

Diagnosis and Treatment of Intracranial Stenoses.

Stroke is one of the most frequent and most significant vascular diseases. According to estimates, 16.9 million people suffered a stroke in 2010, and over one-third of the incidents were lethal. The risk of suffering a stroke due to intracranial stenosis is between 7 and 24%. As opposed to extracranial stenoses of the internal carotid artery, there is no standardized treatment concept for intracranial stenoses. At present, treatment with a low daily dose of 100 mg aspirin is recommended by the guidelines for intracranial stenoses to additionally prevent dose-dependent gastrointestinal side effects and bleeding complications. The WINGSPAN study showed stroke rates and mortality rates amounting to 4.5% after 30 days and 7.0% after 6 months. The Stenting versus Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis study is a randomized, multicenter study that compared endovascular stent treatment in patients with symptomatic arteriosclerotic intracranial stenoses with intensified drug therapy. After the inclusion of 451 of 764 study patients planned initially, study recruitment was terminated prematurely because the stroke rate or mortality rate within 30 days was 14.7% in the endovascular treatment group compared with 5.8% in the drug therapy group and 20% within 12 months compared with 12.2%. Quite recently the results of a second randomized study of intracranial stents were published in the Vitesse Intracranial Stent Study for Ischemic Stroke Therapy study. In an analysis published by Liebeskind et al. concerning the impact of collateral vessels on the stroke risk based on data from the Warfarin-Aspirin Symptomatic Intracranial Disease study, it was demonstrated that a sufficiently formed collateral network in patients with high-degree vascular constrictions (≥ 70%) plays a crucial role in the avoidance of strokes. If there is no system of collateral vessels or if it is insufficient, the stroke risk in the dependent vascular territory is six times higher. So far it has not yet been possible to conclusively answer the question of optimal treatment for intracranial stenoses. There is particularly need for action regarding the treatment of high-degree recurrent symptomatic stenoses, not only in light of the unfavorable prognosis but also within the scope of demographic change.

Evaluation of the pontine perforators of the basilar artery using digital subtraction angiography in high resolution and 3D rotation technique.

BACKGROUND AND PURPOSE: Compromise of perforating branches of the basilar artery resulting in brain stem infarctions has been described as a major complication of intracranial stent placement for basilar artery stenosis or after implantation of endovascular flow diverters. Descriptions of pontine arteries are mainly based on examinations of injection specimens; however, there is a lack of consistent presentation of the small branches of the basilar artery in the imaging literature. Therefore, we retrospectively analyzed DSA images and 3D rotational angiography with a review of literature for an imaging definition of microvascular anatomy of the brain stem. MATERIALS AND METHODS: We retrospectively analyzed 2k DSA images (detector format 32 × 32 cm; image matrix 2480 × 1920 pixels) and 3D rotational angiography reconstructions (5 second DSA, subtraction technique) obtained on Axiom Artis zee biplane neuroradiologic angiography equipment using standard protocol. RESULTS: On 2D and 3D DSA images, small arterial side branches of the basilar artery can be demonstrated in each of the cases but with a wide variation in the visibility of these vessels. Compared with 2D DSA images, 3D DSA reconstructions allow superior visualization of the small branches of the basilar artery. CONCLUSIONS: Our results demonstrate that 2D DSA and 3D-rotation techniques are able to reliably visualize the penetrating branches of the brain stem in vivo. No zone of basilar artery is free from important side branches. Collateral pathways between circumferential and perforating arteries are occasionally detectable. In the future, further refinement of imaging techniques is necessary to increase the reliability of small vessel angiography to use this data for risk assessment before stent placement and aneurysm treatment.

Flat panel detector computed tomography for the interaction between contrast-enhanced thrombi and stent retrievers in stroke therapy: a pilot study.

OBJECTIVES: The purpose of this study was to create virtual 3D views of the interaction between contrast-enhanced thrombi and three different types of stent retrievers. MATERIALS AND METHODS: Artificial thrombi with and without contrast agent were created and introduced into a silicone tube with saline solution. The stent retrievers (Aperio (A), Solitaire FR (B), Revive (C)) were released around the thrombi. For each retriever, two sets (0 min, 5 min) of flat panel computed tomography (CT) data were acquired on a Siemens Axiom Artis Zee biplane angiography system and reconstructed using syngo InSpace 3D software. RESULTS: The filaments of all three stent retrievers were displaced by the thrombus immediately after deployment. Another study series after 5 min showed further expansion of the stents into the thrombus. A tends to appose best around obstacles. A and B allow cushion-like bulging of clot material into the stent lumen. C showed only moderate curvilinear bulging and a minor degree of interaction in between stent filaments and thrombus. CONCLUSIONS: Flexible design allows better apposition of the device to the surface of the thrombus. A relatively strong longitudinal structure combined with large gaps in between the stent filaments seems to favor migration into the clot. The main capture mechanism seems to be engagement of the clot between the crossings of stent struts.

Metabolic changes in patients with aneurysmal subarachnoid hemorrhage apart from perfusion deficits: neuronal mitochondrial injury?

BACKGROUND AND PURPOSE: Neuronal damage in aSAH apart from perfusion deficits has been widely discussed. We aimed to test if cerebral injury occurs in aSAH independently from visible perfusion deficit by measuring cerebral metabolites in patients with aSAH without infarction or impaired perfusion. MATERIALS AND METHODS: We performed 3T MR imaging including (1)H-MR spectroscopy, DWI, and MR perfusion in 58 patients with aSAH and 11 age-matched and sex-matched control patients with incidental aneurysm. We compared changes of NAA, Cho, Glx, Lac, and Cr between all patients with aSAH and controls, between patients with and without visible perfusion deficit or infarction and controls, and between patients with and without visible perfusion deficit or infarction by using the Wilcoxon signed-rank test. RESULTS: We found that NAA significantly (P < .005) decreased in all patients with aSAH. Cho was significantly increased in all patients compared with controls (P < .05). In patients without impaired perfusion or infarction, Glx was significantly decreased compared with both controls (P = .005) and patients with impaired perfusion or infarction (P = .006). CONCLUSIONS: The significant decrease of NAA and Glx in patients with aSAH but without impaired perfusion or infarction strongly suggests global metabolic changes independent from visible perfusion deficits that might reflect neuronal mitochondrial injury. Further, impaired perfusion in aSAH seems to induce additional metabolic changes from increasing neuronal stress that might, to some extent, mask the global metabolic changes.

Beyond delayed cerebral vasospasm: infarct patterns in patients with subarachnoid hemorrhage.

PURPOSE: Angiographic vasospasm (CVS) has been accused to be the main cause of delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage (SAH). However, treatment success including endovascular treatment remains to be improved. We performed a pattern analysis of ischemic lesions in SAH patients in the absence of angiographic cerebral vasospasm to generate further hypotheses concerning etiology and risk factors of DCI apart from vasospastic narrowing. METHODS: We retrospectively included 309 patients with cerebral infarcts after SAH. Vasospasm was assessed by means of CT or MR angiography and perfusion measurement or digital subtraction angiography. All clinical and radiological data were used to determine the most probable etiology for new infarcts. RESULTS: Twenty-seven percent of patients showed infarcts without presence of angiographic vasospasm. Seventy-three percent of these "atypical infarcts" were induced by complications of aneurysm therapy, 7 % by hypoxia, 2 % by ICP-related herniation. In 17 %, the etiology remained unclear; however, disturbances of the microcirculation for different reasons were the most likely cause in these patients. CONCLUSION: Beyond CVS and treatment complications, a not insignificant number of SAH patients suffered from infarcts of other etiology probably due to disturbance of the microcirculation. Therapeutic approaches for vasodilation of angiographic vasospasm alone should be reconsidered.

Long-term outcome after coil embolization of cavernous sinus arteriovenous fistulas.

BACKGROUND AND PURPOSE: Cranial nerve palsies are regularly observed in patients with arteriovenous fistulas of the cavernous sinus. The purpose of our study was to determine the long-term clinical outcome-with a special focus on extra-ocular muscular dysfunctions-in patients who had undergone endovascular treatment of a cavernous sinus fistula with detachable coils. MATERIALS AND METHODS: Sixteen patients were recalled for an ophthalmoneurologic control examination (mean interval of 4.4 years). The mRS and the EQ-5D questionnaire were used for the description of general outcome. Age, duration of symptoms, character of the fistula (direct, dural), and coil volume were tested to assess their relevance for persistent symptoms. RESULTS: All patients displayed complete regression of chemosis, exophthalmus, and pulsating tinnitus with no evidence of recurrences. Oculomotor disturbances persisted in 9 of 13 patients and caused permanent diplopia in 7 patients. In 15 patients a mRS score of 1 or 2 was achieved; however, 7 patients reported some limitations in life quality (EQ-5D). A significant correlation was found between coil volume and persistent diplopia (P = .032) and persistent cranial nerve VI paresis (P = .037). CONCLUSIONS: Coil embolization of the cavernous sinus led to durable closure of AVF and reliable regression of acute symptoms. However, long-term follow-up showed a 44% rate of persistent cranial nerve deficits with disturbances of oculomotor and visual functions. This may be explained by the underlying fistula size itself and/or the space-occupying effect of the coils. As neuro-ophthalmologic outcome is crucial for control of therapeutic success, patients should be routinely examined by ophthalmologists.

[Anatomy of the skull base and the cranial nerves in slice imaging]. / Anatomie der Schädelbasis und Hirnnerven in der Schnittbildgebung.

Computed tomography (CT) and magnetic resonance imaging (MRI) are suitable methods for examination of the skull base. Whereas CT is used to evaluate mainly bone destruction e.g. for planning surgical therapy, MRI is used to show pathologies in the soft tissue and bone invasion. High resolution and thin slice thickness are indispensible for both modalities of skull base imaging. Detailed anatomical knowledge is necessary even for correct planning of the examination procedures. This knowledge is a requirement to be able to recognize and interpret pathologies. MRI is the method of choice for examining the cranial nerves. The total path of a cranial nerve can be visualized by choosing different sequences taking into account the tissue surrounding this cranial nerve. This article summarizes examination methods of the skull base in CT and MRI, gives a detailed description of the anatomy and illustrates it with image examples.