Perianeurysmal Edema Research Articles

Unique image findings around “kissing” distal anterior cerebral artery aneurysms in addition to perianeurysmal edema: A case report

Some aneurysms cause edema formation in the surrounding brain parenchyma and are thought to reflect various phenomena occurring in the aneurysm. Some authors highlighted perianeurysmal edema (PAE) as a finding that indicates higher risk of rupture of the aneurysm. On the other hand, there are no reports of image changes in the surrounding brain parenchyma of aneurysm other than edema formation.We describe a 63-year-old man with unique signal change in the surrounding brain parenchyma of "kissing" distal anterior cerebral artery aneurysms completely different from PAE. The large and partially thrombosed aneurysm presented well-defined signal change surrounding brain parenchyma in addition to PAE. Intraoperative findings revealed the signal change as a space of retaining serous fluid. Drain the fluid and clipping was made for the both anterior cerebral artery aneurysms. The postoperative course was uneventful and his headache was improved the day after the surgery. The perianeurysmal signal change was also disappeared immediately after the surgery except for the PAE.This case demonstrates a rare phenomenon of signal change around the aneurysm, and there is a possibility that the unique finding exists as an early manifestation of intracerebral hematoma associated with aneurysm rupture.

Imaging features of mycotic aortic aneurysms.

Infectious aortitis (IA) is a rare and life-threatening cardiovascular disease. Early diagnosis and timely intervention are crucial for reducing mortality associated with mycotic aortic aneurysms (MAAs); however, early diagnosis is challenging due to the nonspecific symptoms. Some cases are diagnosed at an advanced stage or after developing complications, such as rupture or aortic fistula. Current state-of-the-art imaging modalities-including computed tomography (CT), magnetic resonance imaging (MRI), and 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT-can detect infected aneurysms in clinically suspicious cases. MAA features on imaging include lobulated pseudoaneurysm, indistinct irregular arterial wall, perianeurysmal gas, perianeurysmal edema, perianeurysmal soft tissue mass, aneurysmal thrombosis, and high metabolic activity with increased uptake of FDG. Enlarged lymph nodes are often found adjacent to the aneurysm, while iliopsoas abscess (IPA), spondylitis, and aortic fistulas are commonly associated complications. After surgery or endovascular repair, radiological features-including ectopic gas, peri-graft fluid, thickening of adjacent bowel, pseudoaneurysm formed at the graft anastomosis, and increased uptake of FDG-may indicate an infection of aortic graft. This article provides an overview of the clinical and imaging features of MAAs. Thus, familiarity with the imaging appearances of MAAs may assist radiologists in the diagnosis and facilitation of timely treatment.

Ethic Statement Correction: Peri-Aneurysmal Brain Edema in Native and Treated Aneurysms: The Role of Thrombosis.

Ethic Statement Correction: Peri-Aneurysmal Brain Edema in Native and Treated Aneurysms: The Role of Thrombosis.

Peri-Aneurysmal Brain Edema in Native and Treated Aneurysms: The Role of Thrombosis.

Cerebral peri-aneurysmal edema (PE) is typically associated with giant partially-thrombosed aneurysms and less frequently with smaller aneurysms treated with endovascular embolization. An understanding of the pathophysiologic mechanism of PE is still limited. We report 3 cases of cerebral aneurysms associated with PE. We describe 2 cases of giant partially thrombosed aneurysms surrounded by vasogenic edema with apposition of an intramural and juxtamural thrombus. Our third case is a smaller aneurysm inciting vasogenic edema several years after coil embolization. Vessel-wall magnetic resonance imaging (MRI) showed avid wall enhancement and an enhancing thrombus embedded within the coils, reflecting inflammation of the aneurysm wall and proliferation of the vasa vasorum. Thrombosis within the aneurysmal sac and walls, both in native and treated aneurysms, may promote inflammatory changes and sustain the occurrence of PE. Vessel-wall MRI has a potential role in the evaluation process of this subgroup of aneurysms.

Perianeurysmal Edema:An Indirect Sign of a Minor Leak from an Intracranial Aneurysm

We report a rare case of perianeurysmal edema(PAE)around the dome of a usual intracranial aneurysm. A 79-year-old woman who presented with a dull headache that had become stronger from a month before was referred to our hospital for further examination of an aneurysm. MR angiogram had detected the aneurysm, having a dumbbell shape and arising from the M2 bifurcation of the right middle cerebral artery. Initial fluid attenuated inversion recovery and T2 weighed images revealed a slightly high intensity area in the brain around the dome of the aneurysm buried in the right temporal lobe, suggesting the presence of PAE possibly due to a preceding minor leak or partial thrombosis or impending rupture of the aneurysm. A CT angiogram revealed bleb formation of the aneurysm(size:10×6 to 4mm)without definite intraluminal thrombosis. The patient and her family consented to emergency craniotomy. During the microsurgical approach, thickening of the arachnoid membrane on the right sylvian fissure was observed. The subarachnoid space between the right frontal and temporal lobes was turbid/adhesive, and deposition of hemosiderin was observed around the aneurysm, indicating a preceding minor bleeding. The aneurysm was successfully clipped, and the postoperative course was uneventful. The present case showed that PAE could be observed even in a usual aneurysm. This finding might be an indirect sign of a preceding minor leak from the aneurysm, particularly when the dome is buried in brain parenchyma or is in close contact with the surrounding brain surface.

Perianeurysmal Edema After Embolization with Flow Diversion

Flow diversion is an endovascular technique for embolization of intracranial aneurysms using a semi-porous stent to that redirects blood flow away from the aneurysm and is a scaffold for vessel remodeling. With flow diversion, aneurysms close slowly over 6-12 months as endothelial growth into the stent covers the neck of the aneurysm. Flow diversion is the preferred treatment for unruptured, large, paraclinoid aneurysms, which are otherwise challenging to treat with conventional open surgical or endovascular techniques. Post-embolization perianeurysmal edema (PAE) is an uncommon complication that occurs weeks to months after embolization and manifests as brain parenchymal edema surrounding the treated aneurysm. The clinical presentation is varied and includes headache, seizure or focal neurologic deficit. Frequently, PAE is misdiagnosed as an embolic stroke, which is a more common post-embolization complication and has some clinical and imaging overlap. PAE can be differentiated from ischemia by the absence of restricted diffusion and aneurysm wall enhancement on post-contrast Magnetic Resonance Imaging (MRI). PAE was initially described following coil embolization, but has subsequently been observed after flow diversion alone or with adjunctive coiling. Post-embolization PAE presumably results from rapid aneurysm thrombosis, endothelial cell necrosis, and the ensuing inflammatory reaction, which spreads to the adjacent brain parenchyma. Early recognition of PAE is critical to initiate appropriate therapy.

Off-Label Uses for Flow Diversion in Intracranial Aneurysm Management.

Treatment of complex aneurysms using microsurgical and other conventional neuroendovascular techniques remains challenging. As a result, stent- and balloon-assisted coiling are instead performed to treat morphologically complex aneurysms, which include giant, wide-necked, and fusiform aneurysms. While these techniques have had success in treating these complex aneurysms, recanalization rates associated with these techniques are still problematic. In the constant effort to improve the outcome of complex aneurysm treatment, flow-diverting stents (FDSs) have emerged in recent years as the preferred treatment. Instead of directly obstructing the flow of blood into the aneurysmal sac, as is the case for stent- and balloon-assisted coiling, FDSs are placed in the parent blood vessel to divert blood flow away from the aneurysm itself. Subsequent to the diverting away of blood from the aneurysm, a thrombotic cascade ensues that ultimately results in the closure of the aneurysm while the parent vessel's perforators are preserved. Current known risks for this procedure include vessel rupture or perforation, in-stent thrombosis, perforator occlusion, procedural or delayed hemorrhages, and perianeurysmal edema. In this review, we will evaluate the mechanisms of actions, clinical applications, complications, and ongoing studies for FDSs.

Perianeurysmal edema: Prevalence, risk factors and clinical significance

Summary Background Perianeurysmal edema is a rare but increasingly reported complication of intracranial aneurysms. However, its pathophysiology remains unclear. Objective We aimed to evaluate the prevalence, risk factors, and clinical significance of perianeurysmal edema. Methods This prospective single-center study included patients with intracranial aneurysms who underwent endovascular treatment between January 2008 and October 2013 and a 3-Tesla MRI follow-up 3 months after treatment. Clinical, anatomic and angiographic variables were prospectively recorded and the MRI blindly reviewed. Perianeurysmal brain edema was defined as high signal intensity on FLAIR images around the aneurysm not corresponding to an arterial territory. Patients with and without perianeurysmal edema were compared using a logistic regression model to identify predictors of perianeurysmal edema. Results Perianeurysmal edema occurred in 20 of 277 patients (7.2%) and 20 of 314 intracranial aneurysms (6.4%) on MRI follow-up 3 months after endovascular treatment. Five patients (25.0%) developed symptoms that could be related to the edema. Aneurysm maximal diameter (OR 1.17, 95%CI [1.04–1.32], P = .01), aneurysm in contact with parenchyma (OR 8.11, 95%CI [1.02–64.93], P = .04) and recurrent aneurysm (OR 3.34, 95%CI [1.08–10.35], P = .03) were independent predictors of perianeurysmal edema. Six out of 8 patients who had complementary injected T1-weighted images presented aneurysmal wall enhancement. Conclusion Perianeurysmal edema is not uncommon, is symptomatic in a quarter of patients and associated with a high rate of recurrence. The risk factors associated with perianeurysmal edema support the concept that its pathogenesis results from a combination of mechanisms such as mass effect, hemodynamic stress and inflammation.

Flow Diversion for Intracranial Aneurysm Management: A New Standard of Care.

Endovascular treatment of intracranial aneurysms with complex morphologies such as giant, wide-necked, or fusiform aneurysms is challenging. Stent-assisted coiling and balloon-assisted coiling are alternative techniques to treat such complex aneurysms, but studies have shown less-than-expected efficacy, as suggested by their high rate of recanalization. The management of complex aneurysms via microsurgery or conventional neuroendovascular strategies has traditionally been poor. However, over the last few years, flow-diverting stents (FDS) have revolutionized the treatment of such aneurysms. FDS are implanted within the parent artery rather than the aneurysm sac. By modifying intra-aneurysmal and parent-vessel flow dynamics at the aneurysm/parent vessel interface, FDS trigger a cascade of gradual intra-aneurysmal thrombosis. As endothelialization of the FDS is complete, the parent vessel reconstructs while preserving the patency of normal perforators and side branch vessels. As with any intervention, the practice and application of flow-diversion technology is inherent, with risks that include vessel rupture or perforation, in-stent thrombosis, perforator occlusion, procedural and delayed hemorrhages, and perianeurysmal edema. Herein, we review the devices, their mechanisms of actions, clinical applications, complications, and ongoing studies.

コイル塞栓術後，動脈瘤周囲浮腫を生じた1 例

コイル塞栓術後，動脈瘤周囲浮腫を生じた1 例

Interobserver variability in the characterization of giant intracranial aneurysms with special emphasis on aneurysm diameter and shape

The Giant Intracranial Aneurysm Registry is a multicenter observational trial exclusively focusing on giant intracranial aneurysms (GIA). As no data exist on the interobserver variability in the radiological description of GIA, there is some uncertainty concerning the reliability of the GIA characteristics included in the registry. We have therefore designed a study to test the interobserver variability in the description of the specific GIA characteristics that are examined in the GIA registry. Six different raters analyzed imaging of five GIA concerning GIA location, GIA size, GIA shape, GIA thrombosis, and the presence of perianeurysmal edema. Interobserver variability was examined using intraclass correlation and Fleiss' kappa analysis. The intraclass correlation coefficient was 0.99 (95 % CI 0.97-1.0) for the largest GIA diameter and 0.98 (95 % CI 0.94-1.0) for the largest GIA diameter in an axial imaging slice. We found perfect interobserver agreement (Fleiss' kappa 1.00) in the characterization of GIA location and the presence of perianeurysmal edema and almost perfect interobserver agreement for GIA thrombosis (Fleiss' kappa 0.86, 95 % CI 0.63-1.00). Only moderate interobserver agreement was found in the description of GIA shape (Fleiss' kappa 0.50, 95 % CI 0.27-0.73). While GIA size, location, thrombosis, and the presence of perianeurysmal edema showed excellent interobserver agreement, the description of GIA shape was achieved with only moderate agreement. Data on GIA shape in multicenter studies, like the GIA registry, should therefore be discussed with caution and potentially reassessed in a centralized fashion.

Perianeurysmal edema in giant intracranial aneurysms in relation to aneurysm location, size, and partial thrombosis.

The underlying mechanisms causing intracranial perianeurysmal edema (PAE) are still poorly understood. Since PAE is most frequently observed in giant intracranial aneurysms (GIAs), the authors designed a study to examine the occurrence of PAE in relation to the location, size, and partial thrombosis (PT) of GIAs along with the clinical impact of PAE. Magnetic resonance imaging data for patients with a diagnosis of unruptured GIA from the international multicenter Giant Intracranial Aneurysm Registry were retrospectively analyzed with regard to location and size of the GIA, PAE volume, and the presence of PT. The occurrence of PAE was correlated to clinical findings. Imaging data for 69 GIAs were eligible for inclusion in this study. Perianeurysmal edema was observed in 33.3% of all cases, with the highest frequency in GIAs of the middle cerebral artery (MCA; 68.8%) and the lowest frequency in GIAs of the cavernous internal carotid artery (ICA; 0.0%). Independent predictors of PAE formation were GIA volume (OR 1.13, p = 0.02) and the occurrence of PT (OR 9.84, p = 0.04). Giant intracranial aneurysm location did not predict PAE occurrence. Giant aneurysms with PAE were larger than GIAs without PAE (p < 0.01), and GIA volume correlated with PAE volume (rs = 0.51, p = 0.01). Perianeurysmal edema had no influence on the modified Rankin Scale score (p = 0.30 or the occurrence of aphasia (p = 0.61) or hemiparesis (p = 0.82). Perianeurysmal edema was associated with GIA size and the presence of PT. As no PAE was observed in cavernous ICA aneurysms, even though they exerted mass effect on the brain and also displayed PT, the dura mater may serve as a barrier protecting the brain from PAE formation.

Prospective Study of Early MRI Appearances following Flow-Diverting Stent Placement for Intracranial Aneurysms.

MR imaging findings of aneurysm enlargement, aneurysm wall enhancement, perianeurysmal edema, and embolic phenomena following deployment of flow-diverting stents may be relevant to those patients who subsequently experience procedure-related intracranial hemorrhage. We sought to document the routine early postoperative MR imaging findings following flow-diverting stent insertion. Patients requiring flow-diverting stent placement for treatment or retreatment of cerebral aneurysms were prospectively included in the study during a 26-month period. Early postprocedural MR imaging studies were obtained and compared with preoperative imaging. Patient clinical outcome data were also collected. There were 34 stent-placement procedures during the study period. Aneurysm mural enhancement and mild new perianeurysmal edema were present in 50% and 14%, respectively. Any DWI lesion was present in 57% of cases. New or possibly new foci of susceptibility effect were found ipsilateral to the stent and not associated with diffusion restriction in 66% of cases. There were 2 cases (6%) of parenchymal hemorrhage and 2 major clinical complications (6%) causing permanent morbidity. Asymptomatic aneurysm mural enhancement is frequently seen following flow-diverting stent placement and should not necessarily be interpreted as a sign of impending aneurysm rupture. This finding often persists despite complete aneurysm occlusion. New small brain parenchymal susceptibility foci following stent placement have not previously been reported, to our knowledge, but were common in our series.

Intracranial aneurysms with perianeurysmal edema: Long-term outcomes post-endovascular treatment

Perianeurysmal edema is rare and is associated with expansion of intracranial aneurysms despite adequate endovascular treatment. The natural history of this condition is poorly understood. We present a case series of perianeurysmal edema to investigate the incidence, natural history and management of these aneurysms. Retrospective analysis of endovascularly treated aneurysms from January 2001 to December 2012 was performed. Perianeurysmal edema either pre- or post-treatment as detected on MRI was used to identify cases. Ten of the 838 patients demonstrated perianeurysmal edema. The median age was 51.5 (interquartile range 48 to 59). Of the 10 subjects, 50% (5/10) were male. Perianeurysmal edema was detected after the initial presentation and treatment in 70% (7/10) of the patients, with one patient developing headache after endovascular coiling, while the remaining 6 were found on routine follow-up imaging. Only 4 of the patients were ever symptomatic in the setting of perianeurysmal edema, with 3 of these patients improved clinically following treatment of the aneurysm. Radiological follow-up showed expanding neck remnants leading to a second endovascular coiling procedure in 50% (5/10) of the patients and a third procedure in 20% (2/10) of the patients to attenuate aneurysm growth. Ten of the aneurysms treated with endovascular therapy in our case series demonstrated perianeurysmal edema. They are mostly asymptomatic, with no cases of re-bleeding identified, however perianeurysmal edema is associated with aneurysm re-expansion despite initial endovascular treatment.

Enhancing brain lesions after endovascular treatment of aneurysms.

Complications of endovascular therapy of aneurysms mainly include aneurysm rupture and thromboembolic events. The widespread use of MR imaging for follow-up of these patients revealed various nonvascular complications such as aseptic meningitis, hydrocephalus, and perianeurysmal brain edema. We present 7 patients from 5 different institutions that developed MR imaging-enhancing brain lesions after endovascular therapy of aneurysms, detected after a median time of 63 days. The number of lesions ranged from 4-46 (median of 10.5), sized 2-20 mm, and were mostly in the same vascular territory used for access. Three patients presented with symptoms attributable to these lesions. After a median follow-up of 21.5 months, the number of lesions increased in 2, was stable in 1, decreased in 3, and disappeared in 1. The imaging and clinical characteristics suggested a foreign body reaction. We could find no correlation to a specific device, but a possible source may be the generic hydrophilic coating.

Aneurysmal wall enhancement and perianeurysmal edema after endovascular treatment of unruptured cerebral aneurysms

Perianeurysmal edema and aneurysm wall enhancement are previously described phenomenon after coil embolization attributed to inflammatory reaction. We aimed to demonstrate the prevalence and natural course of these phenomena in unruptured aneurysms after endovascular treatment and to identify factors that contributed to their development. We performed a retrospective analysis of consecutively treated unruptured aneurysms between January 2000 and December 2011. The presence and evolution of wall enhancement and perianeurysmal edema on MRI after endovascular treatment were analyzed. Variable factors were compared among aneurysms with and without edema. One hundred thirty-two unruptured aneurysms in 124 patients underwent endovascular treatment. Eighty-five (64.4 %) aneurysms had wall enhancement, and 9 (6.8 %) aneurysms had perianeurysmal brain edema. Wall enhancement tends to persist for years with two patterns identified. Larger aneurysms and brain-embedded aneurysms were significantly associated with wall enhancement. In all edema cases, the aneurysms were embedded within the brain and had wall enhancement. Progressive thickening of wall enhancement was significantly associated with edema. Edema can be symptomatic when in eloquent brain and stabilizes or resolves over the years. Our study demonstrates the prevalence and some appreciation of the natural history of aneurysmal wall enhancement and perianeurysmal brain edema following endovascular treatment of unruptured aneurysms. Aneurysmal wall enhancement is a common phenomenon while perianeurysmal edema is rare. These phenomena are likely related to the presence of inflammatory reaction near the aneurysmal wall. Both phenomena are usually asymptomatic and self-limited, and prophylactic treatment is not recommended.

Flow diverters for intracranial aneurysms.

Flow diverters (pipeline embolization device, Silk flow diverter, and Surpass flow diverter) have been developed to treat intracranial aneurysms. These endovascular devices are placed within the parent artery rather than the aneurysm sac. They take advantage of altering hemodynamics at the aneurysm/parent vessel interface, resulting in gradual thrombosis of the aneurysm occurring over time. Subsequent inflammatory response, healing, and endothelial growth shrink the aneurysm and reconstruct the parent artery lumen while preserving perforators and side branches in most cases. Flow diverters have already allowed treatment of previously untreatable wide neck and giant aneurysms. There are risks with flow diverters including in-stent thrombosis, perianeurysmal edema, distant and delayed hemorrhages, and perforator occlusions. Comparative efficacy and safety against other therapies are being studied in ongoing trials. Antiplatelet therapy is mandatory with flow diverters, which has highlighted the need for better evidence for monitoring and tailoring antiplatelet therapy. In this paper we review the devices, their uses, associated complications, evidence base, and ongoing studies.

A Ruptured Basilar Tip Aneurysm Showing Repeated Perianeurysmal Edema after Endovascular Coil Embolization: Case Report

The authors present an extremely rare case of a 48-year-old female who developed repeated perianeurysmal edema at 2, 9, and 16 weeks after endovascular coil embolization for the ruptured intracranial aneurysm. Interestingly, the mechanism for this edema could be different at each time point in this case; acute thrombosis formation, chemical inflammation, and aneurysm recanalization. We have to be aware of this potential complication in the long term after endovascular coil embolization for the intracranial aneurysm, especially with large size or buried into the brain parenchyma. The clinical implications of this case are discussed with a review of the literature.

Surgery for mycotic aneurysm

Backgound Infected aneurysm (or mycotic aneurysm) is defined as an infectious disease of the wall of an artery with formation of a blind, saccular out-pouching that is contiguous with the arterial lumen. Symptoms are frequently absent or non-specific during the early stages. Once clinically presented, infected aneurysms are often at an advanced stage of development and associated with complications such as rupture. Nontreatment or delayed treatment of infected aneurysms has a poor outcome, with high morbidity and mortality rate of fulminant sepsis or hemorrhage. In clinically suspected cases, computed tomography is state –ofthe-art technique used for diagnosis. Imaging features of infected aneurysms include a lobulated vascular mass, an indistinct irregular arterial wall, perianeurysmal edema, and a perianeurysmal soft-tissue mass. Urgent surgery performed for solving aortic rupture, carries high morbidity and mortality rates.

大型未破裂脳動脈瘤に対するコイル瘤内塞栓術

We retrospectively studied the endosaccular coil embolization of 88 patients with 89 large (maximum diameter ≥10 mm) unruptured intracranial aneurysms (UIAs). The mean aneurysm and neck size were 12.7 ±2.9 mm and 5.7±1.8 mm, respectively. Frequent locations were the paraclinoid segment of the internal carotid artery and posterior communicating artery in the anterior circulation and the basilar artery bifurcation in the posterior circulation. Twenty-one aneurysms (23.6%) presented with the clinical symptoms due to the mass effect. All of the procedures were completed. Embolization techniques used were conventional (simple, balloon-assisted, or double-catheter) techniques in 66 aneurysms and the stent-assisted technique in 23 aneurysms. Overall immediate anatomical outcomes showed complete occlusion (CO) in 50.6%, residual neck (RN) in 29.2%, and residual aneurysm (RA) in 20.2%. Overall radiological follow-up results of the 71 aneurysms showed unchanged in 26.8%, improved in 11.3%, minor recurrence in 22.5%, and major recurrence in 39.4%. The final anatomical outcomes of the aneurysms radiologically followed up were CO in 47.9%, RN in 31.0%, and RA in 21.1%. The stent-assisted technique improved the immediate anatomical outcomes and decreased the risk of recurrence in the short term compared with the conventional techniques. Procedure-related complications occurred in 15.9% of the aneurysms. Four aneurysms (4.5%) had ischemic complications, and two aneurysms (2.2%) had hemorrhagic complications. Only four patients had clinical worsening of the mRS of >1 at the latest clinical follow-up. The permanent morbidity and mortality rates were 3.4% and 1.1%, respectively. The mean clinical follow-up period after endovascular therapy was 34.9±2.9 months (13 days–9.54 years). No patients suffered from aneurysmal subarachnoid hemorrhage (SAH) during the clinical follow-up periods. Permanent clinical worsening of the mass effect occurred in three patients with visual symptoms. Two aneurysms showed transient asymptomatic perianeurysmal edema that improved after administration of steroid therapy. Basilar artery dissection and renal artery injury due to the migration of the femoral sheath guidewire occurred once in each case. Twenty-one aneurysms (23.6%) underwent endosaccular coil re-embolization without any complications. No patients underwent surgical clipping or parent artery scarification. The mean duration between the initial treatment and the first re-embolization was 18.2 months (0.5–48.4 months). Endosaccular coil embolization of the large UIAs is effective and safe. But recurrence and aneurysm growth after endosaccular coil embolization are significant concerns, and patients with visual symptoms may be candidates for parent artery occlusion or surgical clipping.