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Rationale and Objectives: Small metallic stents are increasingly used in the treatment of cerebral aneurysms and for revascularization in ischemic strokes. Realistic three-dimensional datasets of a stent were obtained by using three x-ray–based imaging methods in current clinical use. Multislice-CT (MS-CT), C-arm flat detector-CT (C-arm CT, ACT), and flat panel-CT (FP-CT) were compared with high-resolution laboratory MicroCT scans that served as a reference standard. The purpose was to assess and compare the quality and accuracy of current clinical three-dimensional reconstructions of a vascular stents. Material & Methods: A 3 × 20 mm Cypher stent was deployed in a straight polytetrafluoroethylene tube and filled with nondiluted iodine contrast and BaSO4. MS-CT images of the static tube phantom and stent were acquired using GE LightSpeed VCT Series, C-arm CT images were obtained using Artis (DynaCT, Siemens), FP-CT were obtained using a preclinical research CT (GE), and MicroCT images were obtained using eXplore Locus SP (GE). DICOM datasets were analyzed using Amira and Matlab. Results: Because of blooming effects, the maximum intensity projections (MIPs) and volume renderings generated from MS-CT showed significantly increased strut dimensions with no distinction between the regular struts and connector struts while the lumen diameter is artificially reduced. The shape of the reconstructed stent surface differed remarkably from the real stent. C-arm CT and FP-CT volume renderings more accurately represented the struts. Consistently capturing the structure of the connectors and the strut shape definition was highly threshold dependent. The stent lumen was about 30% underestimated by MS-CT when compared to MicroCT. Conclusion: The spatial resolution of current clinical CT for imaging of small metallic stents is insufficient to visualize fine geometrical details. Further improvement in the spatial resolution of clinical imaging technologies combined with better software and hardware for image postprocessing will be necessary for detailed structural analysis, evaluation of the stent lumen in vivo, and to permit accurate assessment of stent patency and early detection potential in-stent stenosis. [Copyright &y& Elsevier]

Abstract: Previous research on the effects of intracranial stents on arterial hemodynamics has involved computational hemodynamics (CHD) simulations applied to artificially generated stent models. In this study, accurate geometric reconstructions of in-vitro (PTFE tube) and ex-vivo (canine artery) deployed stents based on ultra-high resolution MicroCT imaging were used. The primary goal was to compare the hemodynamic effects of deployment in these two different models and to identify flow perturbations due to deployment anomalies such as stent malapposition and strut prolapse, important adverse mechanics occurring in clinical practice, but not considered in studies using idealized stent models. Ultra-high resolution MicroCT data provided detailed visualization of deployment characteristics allowing for accurate in-stent flow simulation. For stent cells that are regularly and symmetrically deployed, the near wall flow velocities and wall shear stresses were similar to previously published results derived from idealized models. In-stent hemodynamics were significantly altered by misaligned or malapposed stent cells, important effects not realistically captured in previous models. This research shows the feasibility and value of an ex-vivo stent model for MicroCT based CHD studies. It validates previous in-vitro studies and further contributes to the understanding of in-stent hemodynamics associated with adverse mechanics of self-expanding intracranial stents. [Copyright &y& Elsevier]

Abstract: The strength and direction of blood flow into and within a cerebral aneurysm are important issues in developing effective interventional strategies to stabilize the aneurysm. We tested the hypothesis that there are significant major hemodynamic features that are common to many aneurysm flows of the type studied here. This was investigated by performing computational fluid dynamic simulations of flow near 7 cerebral aneurysms using geometrical data obtained from clinical CT scans. Our numerical simulations of flow across the ostium plane of an aneurysm show that in many cases there is relatively stable flow structure that is maintained over the phase of the pulsatile flow cycle. The two main features of this flow are (1) quasi-permanent regions of flow influx and efflux across the ostium plane exist, separated by a “virtual boundary”, and (2) a helical vortex flow pattern within the aneurismal sac with swirl in two orthogonal cross-sectional planes. These numerical observations are consistent with in vitro experimental data from ultrasound color-Doppler velocimetry and other numerical and experimental studies. The observed flow patterns are found to occur in different types of aneurysms (bifurcation and sidewall), and can persist even after flow parameters are perturbed beyond the normal range of physiological flow conditions. These results suggest that in many cases, major aspects of the behavior of aneurismal hemodynamics for important classes of aneurysms can be learned from an analysis of steady, non-pulsatile flow, which is simpler and faster to simulate than time-dependent, pulsatile flow. An understanding of this fluid dynamical behavior may also prove useful in the design of stents, coils, and various other endovascular flow diverting devices. [Copyright &y& Elsevier]

Abstract: Haemangioblastomas occur sporadically or in association with Von Hippel-Lindau (VHL) disease. Occasionally, they are associated with intrathecal cauda equina nerve roots and rarely with spinal nerve roots. The occurrence of a completely extrathecal, thoracic spinal nerve haemangioblastoma is exceptional, with only one case previously described in the English-language literature. We report an extradural thoracic spinal nerve haemangioblastoma in a patient with VHL disease causing a progressive thoracic radiculopathy. The advantages of three-dimensional digital angiography will be discussed. Three-dimensional reconstruction of the images acquired by rotational digital subtraction angiography is one of the most promising developments to improve surgical planning for complex vascular lesions. [Copyright &y& Elsevier]

Arteriovenous fistulas (AVFs) involving the cavernous sinus usually become clinically apparent due to eye symptoms. Although rare, the same symptoms can be associated with AVFs located remote from the cavernous sinus when the shunt drains into its tributaries. We report the unusual case of a dural AVF in which such communication was not immediately obvious from the diagnostic angiogram. A 61-year-old male presented with increasing lid swelling, proptosis, and redness of the right eye for 1 month. Digital subtraction angiography showed no evidence of a cavernous sinus fistula but revealed a dural AVF between the right middle meningeal artery and the vein of Trolard. The fistula had a minor drainage through a small superficial middle cerebral vein toward the middle cranial fossa. Late venous-phase images eventually revealed faint opacification of the right cavernous sinus and superior ophthalmic vein. Endovascular treatment was performed by transarterial embolization with complete occlusion of the AVF obtained after 2 sessions. Dural AVFs involving cortical veins may cause atypical symptoms suggesting a cavernous sinus fistula due to remote venous drainage. Understanding venous anatomy helps to correlate vascular pathology and clinical symptoms and thus allows efficient and safe treatment. [ABSTRACT FROM AUTHOR]

Abstract: Background: Traumatic aneurysms of the internal maxillary artery are extremely rare. We report a case of traumatic pseudoaneurysm of the pharyngeal artery, a branch of the internal maxillary artery, presenting with hematemesis and hematochezia. Case Description: An 18-year-old man presented with deep drowsy consciousness after a motor vehicle accident, in which he had a severe craniofacial injury. Three days later, he had hematemesis and hematochezia with a marked decrease in circulating hemoglobin level. External carotid arteriography performed to rule out vascular injury revealed active leakage from a false aneurysm of the pharyngeal artery. The lesion was successfully obliterated by superselective endovascular embolization. Conclusions: In patients with craniofacial injury associated with multiple traumas, traumatic pseudoaneurysm of the pharyngeal artery should be suspected as one of the possible causes of hematemesis and hematochezia. Selective endovascular embolization with cerebral angiography is an effective modality for the treatment and diagnosis of this leison. [Copyright &y& Elsevier]

Background Microcatheter entrapment during embolization of brain arteriovenous malformations (AVMs) represents a potentially harmful technical complication. Although several techniques have been reported for endovascular catheter retrieval from an Onyx cast, such methods have never been demonstrated with acrylic glues. We report a case of removal of a glued microcatheter from an N -butyl cyanoacrylate (NBCA) cast using a microsnare. Methods and Results A 26-year-old woman presented with an intracranial hemorrhage resulting from a ruptured right choroidal AVM. A microcatheter used for transarterial embolization was unintentionally glued into the NBCA cast. Because attempts to remove the catheter by simple traction failed, a microsnare was used and allowed withdrawal of the entrapped microcatheter without causing damage to the cerebral vasculature. The patient woke up without clinical sequelae. Conclusions Although it is not recommended as routine practice, snaring a glued microcatheter is feasible and can be used in selected cases as a last resort if thromboembolic complications are feared. Highlights • A microcatheter entrapped in an N -butyl cyanoacrylate cast can be removed by a snaring technique. • Microcatheter retrieval may be considered in cases with high thromboembolic risks. • Chronically retrained microcatheters may cause serious complications. [ABSTRACT FROM AUTHOR]