Munetaka Yamamoto

Transvenous Embolization of Dural Carotid Cavernous Fistulas: A Series of 44 Consecutive Patients

BACKGROUND AND PURPOSE: Endovascular TVE for DCCF is used for curative purposes, but serious complications can be caused with inadequate embolization. Our aim was to report clinical characteristics, angiographic findings, and results of endovascular TVE in patients presenting with DCCF. MATERIALS AND METHODS: We performed a retrospective analysis of 44 consecutive patients with DCCF treated by TVE. Approach routes, angiographic results, clinical outcomes, and complications were assessed. RESULTS: An approach via the internal jugular vein and inferior petrosal sinus was possible in 90% of patients, with complete occlusion of the fistula in 81.6% of patients. A minor residual shunt remained in 13.6% of patients, while a significant shunt remained in 4.5%. In 4 patients, add-on management with transarterial embolization was useful, and in 2 patients with residual shunt, radiosurgery was used. With long-term follow-up (6–40 months), we encountered recanalization/recurrence in 4 patients (9.1%). Complications were seen in the form of permanent morbidity in 3 patients (7%) and transient morbidity in 6 patients (14%). CONCLUSIONS: For endovascular treatment of DCCF, a transvenous approach was effective in most of our patients; however, some adverse effects were encountered. If AV shunts remain after transvenous treatment, additional modalities must be considered.

Endovascular Therapy of 500 Small Asymptomatic Unruptured Intracranial Aneurysms

BACKGROUND AND PURPOSE: Although the natural course of UIAs remains unclear, the risk of aneurysmal SAH due to small (<10 mm) asymptomatic UIAs is low. Endovascular therapy for UIAs has increased because of device development and the need for less invasive treatment. We report the results, safety, and efficacy of endovascular therapy of small asymptomatic UIAs. MATERIALS AND METHODS: A total of 457 patients with 500 small asymptomatic UIAs (maximum diameter < 10 mm) underwent endosaccular coil embolization at Juntendo University Hospital and affiliated hospitals. We retrospectively evaluated the technical feasibility, immediate and short-to-midterm follow-up anatomic results, procedure-related complications, and clinical outcomes. RESULTS: Endosaccular coil embolization was completed in 481 aneurysms (96.2%) and attempted in 19 (3.8%). Completed aneurysms were treated with the simple (39.5%), balloon-assisted (51.4%), and double-catheter (9.1%) techniques. Immediate angiographic outcomes were CO for 309 (64.2%) aneurysms, RN for 72 (15.0%), and RA for 100 (20.8%). Procedure-related complications occurred in 38 aneurysms (7.6%): 19 ischemic, 11 hemorrhagic, and 8 others. Permanent morbidity and mortality were 0.8% and 0.2%, respectively. Anatomic outcome of 427 aneurysms followed up for >6 months with conventional catheter or MR angiographies showed recanalization in 72 (16.9%) aneurysms, necessitating retreatment in 9.9% (mean, 31.4 months). No patients had aneurysmal SAH during the clinical follow-up period (mean, 34.7 months). CONCLUSIONS: In this series, endovascular therapy of small asymptomatic UIAs was highly feasible with low morbidity and mortality rates.

Assessing Blood Flow in an Intracranial Stent: A Feasibility Study of MR Angiography Using a Silent Scan after Stent- Assisted Coil Embolization for Anterior Circulation Aneurysms

BACKGROUND AND PURPOSE: Blood flow in an intracranial stent cannot be visualized with 3D time-of-flight MR angiography owing to magnetic susceptibility and radiofrequency shielding. As a novel follow-up tool after stent-assisted coil embolization, we applied MRA by using a Silent Scan algorithm that contains an ultrashort TE combined with an arterial spin-labeling technique (Silent MRA). The purpose of this study was to determine whether Silent MRA could visualize flow in an intracranial stent placed in the anterior circulation. MATERIALS AND METHODS: Nine patients treated with stent-assisted coil embolization for anterior circulation aneurysms underwent MRAs (Silent MRA and TOF MRA) and x-ray digital subtraction angiography. MRAs were performed in the same session on a 3T unit. Two neuroradiologists independently reviewed the MRA images and subjectively scored flow in a stent as 1 (not visible) to 4 (excellent) by referring to the latest x-ray digital subtraction angiography image as a criterion standard. RESULTS: Both observers gave MRA higher scores than TOF MRA for flow in a stent in all cases. The mean score for Silent MRA was 3.44 ± 0.53, and for TOF MRA, it was 1.44 ± 0.46 (P < .001). CONCLUSIONS: Silent MRA was able to visualize flow in an intracranial stent more effectively than TOF MRA. Silent MRA might be useful for follow-up imaging after stent-assisted coil embolization, though these study results may be only preliminary due to some limitations.

Endovascular therapy of internal carotid artery bifurcation aneurysms

Background Internal carotid artery (ICA) bifurcation aneurysms are uncommon. Therefore, there have been only a few endovascular series on ICA bifurcation aneurysms published to date. The purpose of this study is to report the safety and efficacy of endovascular therapy for ICA bifurcation aneurysms. Methods There were 25 ICA bifurcation aneurysms (unruptured n=23, ruptured n=2) in 25 patients in this study. There were 14 women, with a mean age of 60.9±10.1 years. All patients underwent endosaccular coil embolization. Results Aneurysm size and neck size ranged from 2.5 to 10.0 mm (mean 5.4±1.5) and from 1.5 to 4.0 mm (mean 2.7±0.8), respectively. Regarding the clinical outcomes of the 23 patients with unruptured aneurysms, 22 patients had no change in their preprocedural modified Rankin Scale (mRS) score. The other patient died of ventilator associated aspiration pneumonia. Two patients with ruptured aneurysms each had scores of mRS 0. Overall morbidity and death rates were 0% and 4%, respectively. 15 aneurysms were treated with a simple technique. The 10 remaining aneurysms required adjunctive techniques: balloon assisted (n=9) and double catheter (n=1). The immediate anatomical outcomes were complete occlusion (n=19 (76.0%)), residual neck (n=4 (16.0%)) and residual aneurysm (n=2 (8.0%)). The overall follow-up of anatomical outcomes were unchanged (n=14 (63.7%)), improved (n=5 (22.7%)) and recurrence (n=3 (13.6%)). No patient suffered from aneurysmal subarachnoid hemorrhage after endovascular therapy. Thromboembolic events without clinical modification occurred in two patients. Conclusions Endovascular therapy of ICA bifurcation aneurysms is safe and effective, with a low risk of recanalization and re-treatment.

A retrospective clinical and angiographic study of the coiling outcome of ruptured intracranial aneurysms

Many factors that determine the outcome of endovascular treatment of ruptured intracranial aneurysms are still controversial. We conducted a retrospective study of 203 patients with ruptured aneurysms treated by coiling to assess these factors. The Glasgow Outcome Scale score was used for clinical follow-up and magnetic resonance angiography for angiographic follow-up. Overall outcome and pretreatment variables predicting outcome were thoroughly analyzed. Good clinical grade on presentation was correlated with a better clinical outcome (p<0.001); however, symptomatic vasospasm (15.8% of patients) was correlated with a worse clinical outcome (p<0.001). Six patients (3%) suffered ischemic complications at the time of treatment, hemorrhagic events occurred in five patients (2.5%), permanent morbidity in five patients (2.5%) and overall mortality in 5.4%. In this series, we studied some factors currently debated in the literature and concluded that elderly patients (> or =65 years) with aneurysmal subarachnoid hemorrhage can safely be treated with endovascular therapy with a favorable outcome and that middle cerebral artery aneurysms can be safely embolized with results comparable to other locations.

Usefulness of Non–Contrast-Enhanced MR Angiography Using a Silent Scan for Follow-Up after Y-Configuration Stent-Assisted Coil Embolization for Basilar Tip Aneurysms

BACKGROUND AND PURPOSE: Y-configuration stent-assisted coil embolization is used for treating wide-neck aneurysms. Noninvasive alternatives to x-ray DSA for follow-up after Y-configuration stent-assisted coil embolization treatment are required. This study aimed to assess the usefulness of non–contrast-enhanced MRA by using a Silent Scan (silent MRA) for follow-up after Y-configuration stent-assisted coil embolization for basilar tip aneurysms. MATERIALS AND METHODS: Seven patients treated with Y-configuration stent-assisted coil embolization for basilar tip aneurysms underwent silent MRA, 3D TOF-MRA, and DSA. Silent MRA and 3D TOF-MRA images were obtained during the same scan session on a 3T MR imaging system. Two neuroradiologists independently reviewed both types of MRA images and subjectively scored the flow in the stents on a scale of 1 (not visible) to 5 (nearly equal to DSA) by referring to the latest DSA image as a criterion standard. Furthermore, we evaluated the visualization of the neck remnant. RESULTS: In all patients, the 2 observers gave a higher score for the flow in the stents on silent MRA than on 3D TOF-MRA. The average score ± standard deviation was 4.07 ± 0.70 for silent MRA and 1.93 ± 0.80 (P < .05) for 3D TOF-MRA. Neck remnants were depicted by DSA in 5 patients. In silent MRA, neck remnants were depicted in 5 patients, and visualization was similar to DSA; however, in 3D TOF-MRA, neck remnants were depicted in only 1 patient. CONCLUSIONS: Silent MRA might be useful for follow-up after Y-configuration stent-assisted coil embolization.

Endothelial cell proliferation in swine experimental aneurysm after coil embolization.

After coil embolization, recanalization in cerebral aneurysms adversely influences long-term prognosis. Proliferation of endothelial cells on the coil surface may reduce the incidence of recanalization and further improve outcomes after coil embolization. We aimed to map the expression of proliferating tissue over the aneurysmal orifice and define the temporal profile of tissue growth in a swine experimental aneurysm model. We compared the outcomes after spontaneous thrombosis with those of coil embolization using histological and morphological techniques. In aneurysms that we not coiled, spontaneous thrombosis was observed, and weak, easily detachable proliferating tissue was evident in the aneurysmal neck. In contrast, in the coil embolization group, histological analysis showed endothelial-like cells lining the aneurysmal opening. Moreover, immunohistochemical and morphological analysis suggested that these cells were immature endothelial cells. Our results indicated the existence of endothelial cell proliferation 1 week after coil embolization and showed immature endothelial cells in septal tissue between the systemic circulation and the aneurysm. These findings suggest that endothelial cells are lead to and proliferate in the former aneurysmal orifice. This is the first examination to evaluate the temporal change of proliferating tissue in a swine experimental aneurysm model.

Radiological changes in infantile dissecting anterior communicating artery aneurysm treated endovascularly. A case report and five-year follow-up.

Intracranial aneurysms are extremely rare in infants, and to our knowledge only seven infants treated for ruptured spontaneous dissecting aneurysms have been reported. Good outcomes have been achieved with endovascular treatment of infantile aneurysm. We the endovascular treatment of a one-month-old girl for ruptured dissecting aneurysm located in the anterior communicating artery, and the unique radiological changes that were observed during the perioperative and follow-up periods. These changes suggest that blood coagulation and fibrinolytic response play a part in the repair and healing processes of dissecting aneurysms. Careful neuroradiological surveys are needed for pediatric dissecting aneurysms treated endovascularly.

Endovascular Therapy for Infectious Intracranial Aneurysm: A Report of Four Cases

BACKGROUND Infectious intracranial aneurysms (IIAs) are rare but can cause substantial morbidity and mortality. We aimed to re-evaluate the role of endovascular therapy for the treatment of IIAs. METHODS This study is a retrospective review of patients diagnosed with IIAs and treated by endovascular therapy in our institutions over the past 13 years. RESULTS Four patients were diagnosed with infectious endocarditis with a total of 5 IIAs. Three of the 4 patients had ruptured IIAs. Two presented with intracerebral hemorrhage, one with subarachnoid hemorrhage, and one with cerebral infarction. The distal middle cerebral artery (MCA) was the most common site, followed by the distal segment of the posterior cerebral artery. Three patients were treated by parent artery occlusion and one by direct aneurysm obliteration. There were no periprocedural complications. One IIA treated by direct aneurysm occlusion was recanalized within 1 year and required a second embolization. Outcomes were measured by the modified Rankin Scale on discharge: 2 patients scored 0, 1 patient scored 1, and 1 patient scored 3. CONCLUSION IIAs located deep in the brain or on the peripheral MCA can be safely treated with endovascular therapy even when they are lying in the eloquent cortex.

Treatment results of endosaccular coil embolization of asymptomatic unruptured intracranial aneurysms in elderly patients

Background and purpose We report the results of endosaccular coil embolization of asymptomatic unruptured intracranial aneurysms (UIAs) in elderly patients (≥65 years). Materials There were 375 elderly patients with 400 asymptomatic UIAs. Patients were divided into two groups: group A included patients aged 65–74 years and group B patients aged ≥75 years. Results Endovascular procedures were completed in 97.8% of patients. Immediate anatomical outcomes showed complete occlusion in 53.7%, residual neck in 18.9%, and residual aneurysm in 27.4%. Anatomical follow-ups (mean 36.3±28.1 months) were unchanged in 55.7%, improved in 22.6%, minor recurrence in 11.5%, and major recurrence in 10.2%. Procedure related complications occurred in 31 patients (8.3%). 15 patients had ischemic and 10 hemorrhagic complications. Retreatments were performed in 16 patients (4.3%). Among 366 patients technically completed, 363 (99.2%) showed a favorable clinical outcome (modified Rankin Scale (mRS) score <1) at 30 days. The remaining three patients showed a worsening of mRS >0 at 30 days. The latest clinical follow-up outcomes showed: mRS score 0 in 362 patients; mRS score 1 in one; mRS score 3 in one; mRS score 4 in one; and mRS score 5 in one patient. Permanent morbidity and mortality rates were 1.1% and 0%, respectively. There were no statistically significant differences in gender, comorbidities, aneurysm size, neck width, dome-to-neck ratio, immediate anatomical outcomes, anatomical follow-up outcomes, or procedure related complications between the groups. Conclusions Endosaccular coil embolization is safe and feasible for elderly patients with asymptomatic UIAs. Old age itself should not be a contraindication.