The white-collar sign after Neuroform Atlas stent-assisted coil embolization of unruptured intracranial aneurysms.

PURPOSE: Although stent-assisted technique is expected to help provide a scaffold for neointima formation at the orifice of the aneurysm, not all aneurysms treated with stent-assisted technique develop complete neointima formation. The white-collar sign (WCS) indicates neointimal tissue formation at the aneurysm neck that prevents aneurysm recanalization. The aim of this study was to explore factors related to WCS appearance after stent-assisted coil embolization of unruptured intracranial aneurysms (UIAs). METHODS: A total of 59 UIAs treated with a Neuroform Atlas stent were retrospectively analyzed. The WCS was identified on digital subtraction angiography (DSA) 1 year after coil embolization. The cohort was divided into WCS-positive and WCS-negative groups, and possible predictors of the WCS were explored using logistic regression analysis. RESULTS: The WCS appeared in 20 aneurysms (33.9%). In the WCS-positive group, neck size was significantly smaller (4.2 (interquartile range (IQR): 3.8-4.6) versus 5.4 (IQR: 4.2-6.8) mm, p = .006), the VER was significantly higher (31.8% (IQR: 28.6%-38.4%) versus 27.6% (IQR: 23.6%-33.8%), p = .02), and the rate of RROC class 1 immediately after treatment was significantly higher (70% vs 20.5%, p < .001) than in the WCS-negative group. On multivariate analysis, neck size (odds ratio (OR): 0.542, 95% confidence interval (CI): 0.308-0.954; p = .03) and RROC class 1 immediately after treatment (OR: 6.99, 95% CI: 1.769-27.55; p = .006) were independent predictors of WCS appearance. CONCLUSIONS: Smaller neck size and complete occlusion immediately after treatment were significant factors related to WCS appearance in stent-assisted coil embolization for UIAs using the Neuroform Atlas stent.

Risk factors and management of intraprocedural rupture during coil embolization of unruptured intracranial aneurysms: role of balloon guiding catheter.

Introduction: Intraprocedural rupture (IPR) is a serious complication of endovascular coil embolization of unruptured intracranial aneurysms (UIAs). Although outcomes after IPR are poor, methods to prevent subsequent neurological deterioration have not yet been investigated. We evaluated the risk factors and management strategies for IPR, particularly the role of balloon guiding catheters (BGCs) in rapid hemostasis. Methods: We retrospectively reviewed all UIA cases treated with coil embolization at three institutions between 2003 and 2021, focusing on preoperative radiological data, operative details, and outcomes. Results: In total, 2,172 aneurysms were treated in 2026 patients. Of these, 19 aneurysms in 19 patients (0.8%) ruptured during the procedure. Multivariate analysis revealed that aneurysms with a bleb (OR: 3.03, 95% CI: 1.21 to 7.57, p = 0.017), small neck size (OR: 0.56, 95% CI: 0.37 to 0.85, p = 0.007), and aneurysms in the posterior communicating artery (PcomA) (OR: 4.92, 95% CI: 1.19 to 20.18, p = 0.027) and anterior communicating artery (AcomA) (OR: 12.08, 95% CI: 2.99 to 48.79, p < 0.001) compared with the internal carotid artery without PcomA were significantly associated with IPR. The incidence of IPR was similar between the non-BGC and BGC groups (0.9% vs. 0.8%, p = 0.822); however, leveraging BGC was significantly associated with lower morbidity and mortality rates after IPR (0% vs. 44%, p = 0.033). Discussion: The incidence of IPR was relatively low. A bleb, small aneurysm neck, and location on PcomA and AcomA are independent risk factors for IPR. The use of BGC may prevent fatal clinical deterioration and achieve better clinical outcomes in patients with IPR.

Intermediate catheter use is associated with complete occlusion and dense packing in coil embolization of unruptured cerebral aneurysms: a propensity score matched study.

BACKGROUND: An intermediate catheter (IMC) can improve the maneuverability and stability of the microcatheter. OBJECTIVE: To investigate the efficacy and safety of using an IMC in triaxial systems for coil embolization of unruptured cerebral aneurysms (UCAs). METHODS: A total of 2430 consecutive saccular UCAs (2259 patients) that underwent initial coil embolization at three institutions between November 2003 and May 2023 were retrospectively reviewed. Patients were classified into two groups: with IMC (IMC(+)) and without IMC (IMC(-)). To investigate whether IMC use increased the rate of complete occlusion and the packing density, a propensity score-matched analysis was used to control for clinical, anatomical, and procedural features. RESULTS: Ultimately, 595 (24.5%) coil embolization used an IMC. Propensity score matching was successful for 424 paired IMC(+) and IMC(-) aneurysms. Compared with the IMC(-) group, the IMC(+) group had significantly higher rate of Raymond-Roy Occlusion Classification class 1 immediately after treatment (30.0% vs 20.8%, P=0.003) and at 6 months (28.8% vs 20.0%, P=0.004) and a higher volume embolization ratio (27.2% (SD 6.5%) vs 25.9% (SD 6.2%), P=0.003). Re-treatment rates were not significantly different between the two groups (0.7% vs 0.2%, P=0.624). No significant differences in the incidences of ischemic and hemorrhagic complications and IMC-related parent artery dissection were found between the two groups. CONCLUSION: Use of IMCs in triaxial systems can provide effective and safe support in coil embolization of UCAs because complete occlusion and dense coil packing can be achieved without increased complications.

Efficacy and safety of fetal posterior cerebral artery stented coil embolization for fetal posterior cerebral aneurysms.

PURPOSE: Aneurysms at the origin of the fetal posterior cerebral artery (fPCA) often show fPCA bifurcation from the aneurysm dome, impeding complete embolization and dense coil packing. The recanalization rate for fPCA aneurysms is therefore high. This study aimed to evaluate the efficacy and safety of stenting into fPCA for aneurysms with fPCA incorporated into the aneurysm to determine whether stenting can provide effective embolization results and prevent recanalization. METHODS: A total of 19 consecutive coil embolization procedures between February 2012 and June 2022 for unruptured fPCA aneurysms with fPCA branching from the dome of the aneurysm were divided into two groups: non-stenting (NS) group (n = 11) and stenting into fPCA (PS) group (n = 8). Data were obtained retrospectively and compared regarding embolization results, complications, and recanalization. RESULTS: Compared with the NS group, the PS group achieved significantly higher complete occlusion rate and packing density (p < 0.001, p = 0.01, respectively). No symptomatic complications were observed in the PS group. Both immediately after stenting and at the 1-year follow-up, no stent kinking, stenosis, occlusion, or malposition were observed in any patients in the PS group. During 1-year follow-up, the cumulative minor and major recanalization-free rate after coil embolization for fPCA aneurysms were significantly higher in the PS group compared with the NS group (p = 0.022, 0.0024, respectively). CONCLUSION: Stenting into fPCA for aneurysms with fPCA incorporated into the aneurysm achieved high-density complete embolization without increasing complications, and prevented recanalization. The fPCA stent-assisted coil embolization can offer an alternative treatment for fPCA aneurysms.

CyberKnife Radiosurgery for Spinal Intramedullary Arteriovenous Malformations: A Single-Center Experience.

BACKGROUND: Intramedullary spinal arteriovenous malformation (ISAVM, glomus type) is a type of spinal cord arteriovenous malformation, which is a rare disease known often to have a complex vascular supply interfering with that of the spinal cord, and is in complex anatomical relations with cord structures and nerve roots. Though microsurgical and endovascular treatment has mainly been the standard options, in high-risk cases with these treatments, stereotactic radiotherapy (SRT) might be the option of choice. METHODS: We retrospectively reviewed 10 consecutive patients with ISAVM who received SRT using CyberKnife at the Japanese Red Cross Medical Center (Tokyo, Japan) from January 2011 to March 2022. RESULTS: No case in this series suffered from hemorrhage after applying SRT. One case experienced neurological impairment 10 years after SRT, which we attributed to venous congestion due to the remaining lesion. No case of radiation myelopathy was observed in this series. In one case, the nidus volume reduction and loss of flow voids were obvious, though improvement in the neurological outcome was not apparent. No radiological changes were observed in the other 9 patients. CONCLUSIONS: Even in lesions without radiological changes, no hemorrhagic events were observed for an average period of 4 years. SRT may be a feasible option in treating ISAVM, especially for lesions in which microsurgical resection and endovascular treatment are inapplicable. To ascertain the safety and efficacy of this approach, further studies with more patients and longer follow-up is required.

Japanese Subarachnoid Aneurysm Trial of Neurosurgical Clipping versus Endovascular Coiling in 1863 Patients with Ruptured Intracranial Aneurysms.

This is a post hoc multivariate analysis of the modified World Federation of Neurosurgical Societies (WFNS) grading project, multicenter prospective observational study including 38 neurosurgical institutions across Japan. Japan Neurosurgical Society WFNS grading committee conducted a modified WFNS grading project as a nationwide prospective registry study. We investigate the clinical outcome of both surgical and endovascular interventions after aneurysmal subarachnoid hemorrhage (SAH) in Japan. A total of 792 patients received surgical intervention and 417 patients received endovascular treatment. Eight hundred patients were female, and 409 patients were male. The mean age was 61.5 ± 13.7 years. At 3 month follow-up, there was no statistically significant difference in good clinical outcome between surgical (68.2%) and endovascular (60.9%) group (odds ratio, 0.89; 95% confidence interval, 0.68-1.16; p = 0.381). Unfavorable outcome rate was 31.8% (238 patients) in the surgical group and 39.1% (154 patients) in the endovascular group. Male, elderly people, modified Rankin scale condition before onset, high-grade modified WFNS clinical grading scale, intracerebral hematoma, posttreatment normal pressure hydrocephalus, and neurological deficit due to symptomatic vasospasm were risk factors for the clinical outcome. Treatment modality was not a statistical factor for clinical outcomes. Surgical clipping has still a major role in the management of SAH in Japan. The present study was not a randomized controlled study, but clinical outcome is not influenced by treatment modalities.

Elongated styloid process as a possible cause of distal carotid artery dissection after carotid endarterectomy using indwelling shunt: A case report.

Background: A dissection beginning from a point distal to the endpoint of the carotid endarterectomy (CEA) is called distal carotid artery dissection (CAD), which is known as one of the significant surgical complications of CEA. Case Description: We present a case of distal CAD as a perioperative complication after CEA using indwelling shunt. We estimated this pathophysiology to be caused by the mechanical conflict of the inflated balloon with the elongated styloid process. Conclusion: Since a distal CAD can cause severe, irreversible neurological deficits, preoperative assessment of the styloid process should be routinely performed in CEA.

Risk factors for recanalization of dense coil packing for unruptured cerebral aneurysms in endovascular coil embolization: Analysis of a single center's experience.

In coil embolization of cerebral aneurysms, inadequate packing is known to increase the probability of recanalization. Even tightly embolized aneurysms may be recanalized, but predictive factors for recanalization have not been fully investigated. This retrospective study aimed to identify risk factors for recanalization of treated aneurysms with a volume embolization ratio (VER) ≥ 25%. A total of 301 unruptured aneurysms in 248 patients who underwent coil embolization between March 2012 and January 2021 were analyzed. Cases involving dissecting aneurysm, intraluminal thrombosis, parent artery occlusion, intraoperative rupture, re-treatment, rupture the day after surgery, postoperative coil migration, and postoperative parent artery occlusion were excluded due to the inaccuracy of VER. A total of 105 aneurysms (34.9%) treated with VER ≥ 25% were extracted. Clinical features (age, sex, medical history, family history), anatomical features (shape, location, aneurysm size, inflow angle, and volume), procedural features (stent-assisted, Raymond-Roy occlusion classification [RROC] immediately after treatment, re-treatment rate), and follow-up period were compared between Recanalization and Non-recanalization groups. Predictors of recanalization were determined using logistic regression and receiver operating characteristic (ROC) curve analyses. Eleven aneurysms were recanalized. In multivariate analysis, RROC class 3 (odds ratio [OR] 11.0; 95% confidence interval [CI] 2.03-59.4) and aneurysm volume (OR 1.005; 95%CI 1.001-1.008) were independent predictors of recanalization. ROC curve analysis showed optimal cutoff values for aneurysm volume of 69.5 mm3 (sensitivity, 81.8%; specificity, 72.3%). In coil embolization of unruptured aneurysms that VER ≥ 25%, cases with RROC class 3 or high aneurysm volume may be associated with a higher risk of recanalization, and should be carefully followed-up.

Characteristics of Unruptured Intracranial Aneurysms with Delayed Rupture Following Coil Embolization: Case Series and Review of the Literature.

Objective: Long-term clinical outcomes including delayed rupture of unruptured intracranial aneurysms (UIAs) after coil embolization (CE) remain unclear. The purpose of this study was to evaluate the precise timing of re-treatment for recanalized UIAs before rupture. Methods: From February 2012 to June 2020, a total of 197 patients with 207 UIAs underwent CE in our institution and were followed up for more than 6 months. The follow-up period, as well as morphological changes from treatment to recanalization, regrowth, and rupture, was retrospectively analyzed. Delayed rupture was defined as a rupture that occurred more than 1 month after CE. Results: The average length of follow-up was 48.7 months. Three of 207 UIAs (1.45%) ruptured after CE. The aneurysm locations were the middle cerebral artery (MCA), anterior communicating artery (AcomA), and internal carotid artery-posterior communicating artery (ICA-Pcomm). The annual rupture rate after CE was 0.36%. Immediately after the first CE, treated aneurysms were graded according to the Modified Raymond-Roy Classification with class II for MCA aneurysms and class IIIb for AcomA and ICA-Pcomm aneurysms. The ICA-Pcomm aneurysm was treated with two additional CEs and was finally graded as class I. In all cases, DSA or MRA before aneurysm rupture showed recanalization and regrowth of aneurysms. The average periods from final embolization to regrowth and from regrowth to rupture were 54.3 months (±16.8) and 2.3 months (±0.9), respectively. Conclusion: UIAs with recanalization and regrowth after CE should undergo re-treatment as early as possible.

Epilepsia Partialis Continua as an Early Sign of Anti-Myelin Oligodendrocyte Glycoprotein Antibody-positive Encephalitis.

Anti-myelin oligodendrocyte glycoprotein (MOG) antibodies have been associated with steroid-responsive cortical encephalitis and comorbid generalized epilepsy. A 44-year-old woman developed repeated epilepsia partialis continua (EPC) without generalized seizures and was anti-MOG antibody-positive. Radiological abnormalities were detected in the bilateral medial frontoparietal cortices, but there were no cerebrospinal fluid abnormalities. She achieved remission with anti-epileptic drugs alone. However, encephalitis recurred four months later when pleocytosis appeared, and steroid therapy was effective. Altogether, EPC without typical cerebrospinal fluid features can be an early sign of anti-MOG antibody-positive encephalitis. Thus, patients with EPC of unknown etiology need to be screened for anti-MOG antibodies.

Refractory De Novo Multiple Cerebral Aneurysms After Radiotherapy and Multistaged "Open" Surgical Treatment for Low-Grade Glioma During Long-Term Follow-Up: A Case Report and Review of the Literature.

BACKGROUND: Radiation-induced aneurysms have been previously reported; however, multiple and repeated de novo aneurysm formation chronologically and anatomically during long-term follow-up have not yet been observed. The pathogenesis of persistent radiation-induced vasculopathy is not fully understood. CASE DESCRIPTION: A 31-year-old woman presented with intraventricular hemorrhage due to rupture of a right internal carotid artery (ICA) aneurysm that developed 17 years after surgical resection of a low-grade glioma in the right frontal lobe and postoperative radiotherapy (focal, 50 Gy/25 fractions). During glioma follow-up, salvage surgery with adjuvant gamma knife therapy and chemotherapy (ranimustine, vincristine, temozolomide) were performed for recurrence of the glioma. The aneurysm was treated with endovascular coil embolization. However, she experienced repeated intraventricular hemorrhages, and angiography revealed a de novo ICA aneurysm. The de novo aneurysms were treated with endovascular surgery using coil embolization and stenting. At 2 years after the third hemorrhage, the surgical wound became dehiscent, probably due to wound infection, thus epicranial soft tissue reconstruction using vascularized skin flap was performed. Despite multistaged endovascular surgery for the ICA aneurysm, she experienced repeated subarachnoid and intraventricular hemorrhages. Angiography revealed a de novo aneurysm of the right posterior cerebral artery and basilar trunk. She underwent coil embolization and stenting. Despite active management with endovascular surgery and close follow-up, she died after an eighth consecutive intraventricular and intracerebral hemorrhage caused by a de novo large aneurysm of the posterior cerebral artery. CONCLUSIONS: To the best of our knowledge, the present study is the first to report on of refractory and recurring de novo aneurysms treated by multistaged endovascular surgery during a long-term follow-up after radiotherapy and multistaged craniotomy for glioma.

Lenalidomide-Induced Ischemic Cerebrovascular Disease in Polyneuropathy, Organomegaly, Endocrinopathy, Monoclonal Gammopathy, and Skin Changes Syndrome.

We describe the case of a 34-year-old woman with polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes (POEMS) syndrome. She developed transient ischemic attack after the introduction of lenalidomide plus dexamethasone (Rd) therapy despite no vascular risk factors. Magnetic resonance and computed tomography angiographies showed bilateral internal carotid artery stenosis. Rd therapy was suspended because of its thromboembolic risk. She had been neurologically stable during the suspension of Rd therapy. After Rd therapy was restarted, however, she repeated ischemic cerebrovascular disease. Rd therapy was switched to carfilzomib plus dexamethasone therapy. Thereafter, she had been neurologically stable. Multivessel stenosis is infrequently seen in POEMS syndrome. Therefore, magnetic resonance angiography should be performed before introducing Rd therapy in POEMS syndrome.

[Outcome of Coil Embolization for Subarachnoid Hemorrhage Accompanied with Intracerebral Hematoma].

OBJECT: Aneurysmal subarachnoid hemorrhage(SAH)associated with intracerebral hematoma(ICH)typically has a poor outcome. SAH with ICH tends to have a worse prognosis than SAH alone. The aim of the present study was to evaluate whether coil embolization during endovascular surgery with ventricle drainage and without ICH evacuation is an appropriate treatment. METHODS: A retrospective review was conducted between March 2012 and May 2015. Thirteen patients with SAH with ICH who underwent coil embolization were retrospectively analyzed. Modified Rankin Scale(mRS)scores were compared for postoperative clinical outcomes of different hematoma locations. RESULTS: All ruptured aneurysms in the present series of patients were treated using endovascular surgery. Six patients underwent additional ventricle drainage. Only one patient underwent craniotomy for evacuation of the hematoma following coil embolization. Despite ten out of thirteen patients(76.9%)having a preoperative SAH clinical grade, as evaluated using the World Federation of Neurosurgical Societies grading system of IV or V, six(46.2%)patients had a favorable outcome(mRS=0-2). CONCLUSIONS: Coil embolization for ruptured aneurysms, especially those located in the frontal lobe, with ICH and without cerebral herniation may be a feasible alternative and less invasive treatment.

Risk Analysis of Unruptured Intracranial Aneurysms: Prospective 10-Year Cohort Study.

BACKGROUND AND PURPOSE: The natural history of unruptured intracranial aneurysms remains unclear, and management strategy is not well defined. METHODS: From January 2003 to December 2012, we enrolled patients with aneurysm in our institution. In total, 2252 patients with 2897 aneurysms were eligible for analysis, and 1960 eligible aneurysms were conservatively managed. Precise 3-dimensional evaluation was conducted using computed tomography angiography, digital subtraction angiography, or magnetic resonance angiography. We then assessed the risk of aneurysm rupture, mortality, and morbidity associated with aneurysm characteristics, demographics, and known health/lifestyle risk factors. RESULTS: The mean follow-up duration was 7388 aneurysm-years. During observation, 56 aneurysms ruptured, resulting in an overall rupture rate per year of 0.76% (95% confidence interval, 0.58-0.98). The mean initial visit to rupture interval was 547 days. Aneurysm size, location, daughter sac, and history of subarachnoid hemorrhage were significant independent predictors for aneurysm rupture. Aneurysms that were ≥5 mm were associated with a significantly increased risk of rupture when compared with 2- to 4-mm aneurysms (unadjusted hazard ratio, 12.24; 95% confidence interval, 7.15-20.93). Of 56 patients who experienced hemorrhage, 29 (52 %) died or were rendered severely disabled. Of the patients who had large or giant aneurysms, none recovered without deficits, and the mortality rate after rupture was 69%. For aneurysms sized <5 mm, the mortality rate was 18%. CONCLUSIONS: Larger aneurysms are at greater risk for rupture and poor outcome. Ethnic factors may play a role in the risk of rupture.

Slow progression of calcified cerebellar metastasis from ovarian cancer: a case report and review of the literature.

The report describes a rare case of a patient with a calcified cerebellar metastasis arising from a primary ovarian cancer. The patient was a 33-year-old woman with a long history of stage IIIc ovarian cancer who had undergone transabdominal hysterectomy and bilateral oophorectomy followed by chemotherapy with gemcitabine hydrochloride. Incidentally, computed tomography (CT) revealed a cerebellar tumor with calcification. The size of the tumor gradually increased, and lateral suboccipital craniotomy was performed for gross total removal of the tumor. The histological diagnosis was ovarian mucinous adenocarcinoma. The patient's postoperative course was uneventful, and she was discharged two days after surgery. Brain metastases from ovarian cancer are rare. In the review of metastatic brain tumors arising from a primary ovarian cancer in the Department of Obstetrics and Gynecology at our institution, this phenomenon was noted in only 10 cases (0.24%) of 4,158 patients with ovarian cancer seen at our center over a period of 8 years. Moreover, only three cases of calcified metastatic brain tumor have been reported previously. In conclusion, complete tumor resection may be an acceptable approach for patients with calcified metastatic tumors both for therapeutic considerations and to obtain tissue for confirmation of histopathological diagnosis. Metastatic brain tumors can be calcified, and should be considered within the differential diagnosis of calcified intracranial lesions to avoid any delay in diagnosis or treatment.

Combined surgical and endovascular treatment of complex cerebrovascular diseases in the hybrid operating room.

BACKGROUND: Although most neurovascular diseases can be treated either by microsurgical or endovascular means, a subset of patients may require a combined approach. Patient transfer from the operating room (OR) to the angiosuite has been a fundamental drawback of this type of approach. OBJECTIVE: The purpose of this study is to report our clinical experience performing combined surgical and endovascular procedures for neurovascular diseases in the hybrid OR. METHODS: 29 patients with neurovascular diseases underwent combined endovascular and surgical procedures in a single session: 16 were scheduled combined treatment and 13 were emergency combined procedures. Of the emergency cases, three were rescue surgeries after endovascular complications. Three patients had ruptured intracranial aneurysms, eight had unruptured intracranial aneurysms, eight had arteriovenous malformations and eight had arteriovenous fistulae; two patients had either a spinal tumor or dural arteriovenous fistulae. RESULTS: All combined procedures were performed in a single session without changing the patient's surgical position. In cases of ruptured arteriovenous malformations or aneurysms with hematoma, an emergency embolization was performed to assist the surgical procedure. Combined superficial temporal artery-middle cerebral artery (STA-MCA) bypass followed by endovascular parent artery trapping were successfully performed for complex large or giant aneurysms. There were two periprocedural ischemic complications. Of the three patients who underwent surgical rescue after endovascular complications, two remained intact and one died despite immediate surgical procedures. CONCLUSION: A combined endovascular and surgical approach conducted in a hybrid OR provides a new strategy for the treatment of complex neurovascular diseases.

Robotic digital subtraction angiography systems within the hybrid operating room.

BACKGROUND: Fully equipped high-end digital subtraction angiography (DSA) within the operating room (OR) environment has emerged as a new trend in the fields of neurosurgery and vascular surgery. OBJECTIVE: To describe initial clinical experience with a robotic DSA system in the hybrid OR. METHODS: A newly designed robotic DSA system (Artis zeego; Siemens AG, Forchheim, Germany) was installed in the hybrid OR. The system consists of a multiaxis robotic C arm and surgical OR table. In addition to conventional neuroendovascular procedures, the system was used as an intraoperative imaging tool for various neurosurgical procedures such as aneurysm clipping and spine instrumentation. RESULTS: Five hundred one neurosurgical procedures were successfully conducted in the hybrid OR with the robotic DSA. During surgical procedures such as aneurysm clipping and arteriovenous fistula treatment, intraoperative 2-/3-dimensional angiography and C-arm-based computed tomographic images (DynaCT) were easily performed without moving the OR table. Newly developed virtual navigation software (syngo iGuide; Siemens AG) can be used in frameless navigation and in access to deep-seated intracranial lesions or needle placement. CONCLUSION: This newly developed robotic DSA system provides safe and precise treatment in the fields of endovascular treatment and neurosurgery.

Comparing accuracy of cerebral aneurysm size measurements from three routine investigations: computed tomography, magnetic resonance imaging, and digital subtraction angiography.

Modern imaging technologies, such as computed tomography (CT) angiography, magnetic resonance (MR) angiography, and digital subtraction (DS) angiography are widely used for pretreatment evaluation of cerebral aneurysms, but the relative accuracies of these modalities are unclear. This study compared the measurements of aneurysm neck and dome height and width on CT angiography, time-of-flight (TOF)-MR angiography, and DS angiography using a three-dimensional workstation. An elastic model of a side-wall aneurysm was connected to an artificial heart pulsatile circuit system. The aneurysm model was prepared using a silicone membrane of 0.6-mm thickness under normal physiological circulation parameters. Using this aneurysm model, three-dimensional TOF-MR angiography, contrast-enhanced CT angiography, and DS angiography were performed. Source images were post-processed on a dedicated workstation to calculate the aneurysm size. DS angiography measurements were found to be the most accurate. In contrast, aneurysm neck sizes measured on CT angiography were significantly wider than actual values (p < 0.05) and aneurysm heights measured using TOF-MR angiography were significantly lower than actual values (p < 0.01). In this in-vitro model, at least one aneurysm dimension measured with CT angiography and with TOF-MR angiography differed significantly from actual values. Aneurysm neck width markedly affects therapeutic planning, as a wide neck requires craniotomy or endovascular treatment using an adjunctive device, so inaccuracies should be considered when aneurysm treatment is planned using modern methods of visualization.

Endovascular treatment of experimental aneurysms using a combination of thermoreversible gelation polymer and protection devices: feasibility study.

OBJECTIVE: We developed a new liquid embolic agent, an aqueous solution of thermoreversible gelation polymer (TGP) for the treatment of cerebral aneurysms. This polymer solution has the unique characteristics that allow it to solidify at a specific temperature without solvent. We performed an experimental aneurysm embolization using this liquid embolic agent with and without different protective devices to evaluate its technical feasibility for the treatment of aneurysms. METHODS: Fourteen side-wall aneurysms were surgically constructed on 14 common carotid arteries of 7 swine. Embolizations were conducted in combination with balloon protection (balloon group, n = 4), microstent protection (stent group, n = 4), and microcoil and microstent protection (stent-coil group, n = 4). Two aneurysms were used as controls. One control aneurysm was not embolized, and the other received control stent placement only. Angiographic follow-up was performed on day 14 and was followed by histopathological evaluation. RESULTS: Successful TGP solution delivery was conducted in all cases. Complete aneurysm occlusion was achieved in all cases without TGP migration. Follow-up angiograms demonstrated complete occlusion in the stent and stent-coil groups. A small recurrence was observed in the balloon group. Histopathological findings demonstrated neoendothelialization across the necks of the aneurysms. CONCLUSION: Experimental aneurysms were safely embolized using TGP. Further modifications related to mechanical stability and long-term safety evaluation results are necessary before clinical application.