Clinical and Hemodynamic Features of Aneurysm Rupture in Coil Embolization of Intracranial Aneurysms.

Intraprocedural rupture (IPR) during coil embolization (CE) of an intracranial aneurysm is a significant clinical concern that necessitates a comprehensive understanding of its clinical and hemodynamic predictors. Between January 2012 and December 2023, 435 saccular cerebral aneurysms were treated with CE at our institution. The inclusion criterion was extravasation or coil protrusion during CE. Postoperative data were used to confirm rupture points, and computational fluid dynamics (CFD) analysis was performed to assess hemodynamic characteristics, focusing on maximum pressure (Pmax) and wall shear stress (WSS). IPR occurred in six aneurysms (1.3%; three ruptured and three unruptured), with a dome size of 4.7 ± 1.8 mm and a D/N ratio of 1.5 ± 0.5. There were four aneurysms in the internal carotid artery (ICA), one in the anterior cerebral artery, and one in the middle cerebral artery. ICA aneurysms were treated using adjunctive techniques (three balloon-assisted, one stent-assisted). Two aneurysms (M1M2 and A1) were treated simply, yet had relatively small and misaligned domes. CFD analysis identified the rupture point as a flow impingement zone with Pmax in five aneurysms (83.3%). Time-averaged WSS was locally reduced around this area (1.3 ± 0.7 [Pa]), significantly lower than the aneurysmal dome (p < 0.01). Hemodynamically unstable areas have fragile, thin walls with rupture risk. A microcatheter was inserted along the inflow zone, directed towards the caution area. These findings underscore the importance of identifying hemodynamically unstable areas during CE. Adjunctive techniques should be applied with caution, especially in small aneurysms with axial misalignment, to minimize the rupture risk.

Non-sinus type of transverse sinus dural arteriovenous fistulas on the arachnoid granulation of the dural sinus wall.

Background: The etiology of a non-sinus-type dural arteriovenous fistulas (DAVFs) with shunt points located on the sinus wall, previously described as on-the-wall-type DAVFs, is unknown. Case Description: Two cases of non-sinus-type transverse sinus DAVF with a shunt point limited to the dural sinus wall, causing cortical venous reflux, were successfully treated with endovascular transarterial Onyx embolization. The Onyx cast showed multiple feeders from the occipital and middle meningeal arteries aggregated in the arachnoid granulation (AG), which dilated the draining vein. Conclusion: Non-sinus-type DAVFs with shunt points located on the AG may be one of the presentations of an on-the-wall-type DAVF.

Usefulness of Y-shaped PulseRider-assisted coil embolization for basilar artery tip aneurysm with a misaligned axis: A case report.

Background: Endovascular treatment of wide-necked bifurcation aneurysms remains challenging. Although the advent of PulseRider and Web has expanded treatment options, aneurysms with a large deviation from the parent artery axis remains difficult to treat. We present the case of a wide-necked bifurcation aneurysm that was misaligned with the angle between the long axis of the parent artery and the aneurysm and was successfully treated with Y-shaped PulseRider-assisted coil embolization. Case Description: A 64-year-old woman presented with an unruptured basilar tip aneurysm. Cerebral angiography showed a wide-necked aneurysm measuring 8.1 mm × 6.1 mm, neck 5.7 mm. The aneurysm was strongly tilted to the right and posterior relative to the basilar artery, and the bilateral posterior cerebral artery (PCA) and superior cerebellar artery (SCA) diverged from the aneurysm body. PulseRider-assisted coil embolization was performed. A Y-shaped PulseRider was selected to be placed in a hybrid fashion with the right arch in the aneurysm and the left arch in the branch. Adequate coil embolization with preservation of the bilateral PCA and SCA was possible, and cerebral angiography immediately after the treatment showed slight dome filling. Cerebral angiography 6 months after the procedure showed that the embolic status had improved to complete occlusion. Conclusion: For wide-neck bifurcation aneurysms with a misaligned axis, a Y-shaped PulseRider used in a hybrid fashion, in which the leaflet on the side with the tilted axis is placed in the aneurysm, allows the PulseRider to be deployed more closely to the aneurysm, thereby enabling good coil embolization.

Investigation of Mechanical Thrombectomy in Elderly Patients over 85 Years Old: A Multicenter Study.

In Japan, which has a super-aging society, there are increasing opportunities to perform mechanical thrombectomy for the elderly; however, there is no recorded evidence of thrombectomy for the elderly. This study examined the usefulness of thrombectomy in the elderly. We retrospectively analyzed patient data using a multicenter acute ischemic stroke registry (NGT-FAST). We examined outcomes in patients 75 years and older who underwent thrombectomies between January 1, 2021, and December 31, 2021. The patients were divided into two groups: the 75-84-year-old group and the 85+-year-old group. There was no difference in the pretreatment National Institutes of Health Stroke Scale score or Alberta Stroke Program Early Computed Tomography Score between the two groups, but the 85+-year-old group had a significantly lower rate of pre-stroke modified Rankin Scale (mRS) score of 0-2. There were no differences in time from onset to treatment or effective recanalization rate, but complications tended to be more common in the 85+-year-old group. The number of patients with a good outcome at discharge (an mRS score of 0-3) was significantly lower in the 85+-year-old group than in the 75-84-year-old group. In addition, 90.9% of patients in the 85+-year-old group with a pre-stroke mRS score of 3 deteriorated after treatment. The pre-stroke mRS score is very important in determining the indication for thrombectomy in the elderly because their preoperative condition is more likely to influence the outcome than that of younger patients.

Superior Visualization of Neovascularization with Silent Magnetic Resonance Angiography Compared to Time-of-Flight Magnetic Resonance Angiography After Bypass Surgery in Moyamoya Disease.

OBJECTIVE: The evaluation of postsurgical neoangiogenesis in patients with moyamoya disease (MMD) is crucial for appropriate patient management. This study aimed to assess the visualization of neovascularization after bypass surgery using noncontrast-enhanced silent magnetic resonance angiography (MRA) with ultrashort echo time and arterial spin labeling. METHODS: After bypass surgery, 13 patients with MMD were followed up for >6 months between September 2019 and November 2022. They underwent silent MRA in the same session as time-of-flight magnetic resonance angiography (TOF-MRA) and digital subtraction angiography (DSA). Two observers independently rated the visualization of neovascularization in both types of MRA from 1 (not visible) to 4 (nearly equal to DSA), with reference to DSA images as the standard. RESULTS: The mean scores were significantly higher for silent MRA compared with TOF-MRA (3.81 ± 0.48 and 1.92 ± 0.70, respectively) (P < 0.01). The intermodality agreements were 0.83 and 0.71 for silent MRA and TOF-MRA, respectively. TOF-MRA depicted the donor artery and recipient cortical artery after direct bypass surgery, although fine neovascularization developed after indirect bypass surgery was poorly visualized. Silent MRA could reveal the developed bypass flow signal and perfused middle cerebral artery territory, which was almost equal to the DSA images. CONCLUSIONS: Silent MRA achieves better visualization of postsurgical revascularization in patients with MMD than TOF-MRA. Moreover, it may have the potential to provide visualization of the developed bypass flow equivalent to DSA.

Preoperative three-dimensional multifusion imaging aiding successful microvascular decompression of a cerebellopontine angle lipoma: associated hemifacial spasm. Illustrative case.

BACKGROUND: Cerebellopontine angle (CPA) lipoma-associated hemifacial spasm (HFS) is rare. As the removal of CPA lipomas has a high risk of worsening the neurological symptoms, surgical exploration is warranted only in selected patients. Preoperative identification of the lipoma affected site of the facial nerve, and offending artery are crucial for patient selection and successful microvascular decompression (MVD). OBSERVATIONS: Presurgical simulation using three-dimensional (3D) multifusion imaging showed a tiny CPA lipoma wedged between the facial and auditory nerves, as well as an affected facial nerve by the anterior inferior cerebellar artery (AICA) at the cisternal segment. Although a recurrent perforating artery from the AICA anchored the AICA to the lipoma, successful MVD was achieved without lipoma removal. LESSONS: The presurgical simulation using 3D multifusion imaging could identify the CPA lipoma, affected site of the facial nerve, and offending artery. It was helpful for patient selection and successful MVD.

Successful Treatment of Acute Uric Acid Nephropathy with Rasburicase in a Primary Central Nervous System Lymphoma Patient Showing a Dramatic Response to Methotrexate-Case Report.

BACKGROUND: Primary central nervous system lymphomas (PCNSLs) are sensitive to chemotherapy. The standard treatment is high-dose methotrexate (MTX)-based chemotherapy. There are no reports of successful treatment of acute uric acid nephropathy with rasburicase after MTX administration in PCNSLs. CASE PRESENTATION: A 54-year-old man with a history of gout presented with a change in character and cognitive dysfunction. MRI showed a large enhancing mass spanning the bilateral frontal lobes and the right temporal lobe. After endoscopic biopsy, an MTX, procarbazine, and vincristine (MPV) regimen was initiated for the treatment of the PCNSL. After the initiation of chemotherapy, the patient experienced a gout attack, and blood examination revealed acute renal failure (ARF) and hyperuricemia. The considered causes of ARF included MTX toxicity and acute uric acid nephropathy. As the dramatic effect of MTX was observed, treatment was continued despite ARF, most probably due to acute hyperuricemia due to tumor lysis, which was treated in parallel. After an improvement in renal function, MTX was resumed, and rasburicase was initiated to control hyperuricemia. A complete response was obtained after induction chemotherapy. Hyperuricemia was controlled with rasburicase, and renal function was preserved. CONCLUSIONS: Acute uric acid nephropathy should be considered when ARF occurs after the initiation of MTX in PCNSLs, especially in newly diagnosed PCNSL patients with large tumors or hyperuricemia.

Elucidating the multiple genetic alterations involved in the malignant transformation of a KRAS mutant neurenteric cyst. A case report.

Neurenteric cyst (NC) shows benign histopathology and rarely demonstrate malignant transformation. We herein describe a case of NC that exhibited malignant transformation. A 65-year-old female presented with gait disturbance due to compression by a cystic mass on the dorsal surface of the medulla oblongata. Partial resection was performed twice, leading to improvement of her symptoms. Two years after the second surgery, gadolinium-perfused T1-weighted magnetic resonance imaging revealed an invasive lesion with contrast enhancement at the trigone of the left lateral ventricle for which partial resection followed by radiotherapy was performed. However, mass regrowth was observed, with the patient eventually succumbing to her disease 11 months after her third surgery. Histopathological analyses of the first and second surgical specimens identified pseudostratified cuboidal epithelial cells, with no nuclear or cellular atypia resembling gastrointestinal mucosa, lining the inner surface of the cystic wall. Based on these findings the lesion was diagnosed as NC. The third surgical specimen exhibited apparent malignant features of the epithelial cells with elongated and hyperchromatic nuclei, several mitotic figures, small necrotic foci, and a patternless or sheet-like arrangement. Based on these findings, the lesion was diagnosed as NC with malignant transformation. Next-generation sequencing revealed KRAS p.G12D mutation in all specimens. Additionally, the third surgical specimen harbored the following 12 de novo gene alterations: ARID1A loss, BAP1 p.F170L, CDKN1B loss, CDKN2A loss, CDKN2B loss, FLCN loss, PTCH1 loss, PTEN loss, PTPRD loss, SUFU loss, TP53 loss, and TSC1 loss. The aforementioned results suggest that KRAS mutation is associated with the development of the NC, and that the additional gene alterations contribute to malignant transformation of the NC.

Non-contrast-enhanced silent magnetic resonance angiography for assessing cerebral aneurysms after PulseRider treatment.

PURPOSE: Conventional time-of-flight (TOF) magnetic resonance angiography (MRA) failed to depict clear visualization of coiled cerebral aneurysms with PulseRider due to metal-induced susceptibility artifacts. Our aim was to overcome the metal artifact using a novel imaging technique of non-contrast-enhanced ultrashort echo-time magnetic resonance angiography (UTE-MRA). MATERIALS AND METHODS: Five unruptured intracranial aneurysms were treated using PulseRider and the patients underwent silent MRA (UTE-MRA). The images were compared with TOF-MRA and digital subtraction angiography (DSA). RESULTS: Silent MRA can visualize the residual cavity of the coiled aneurysms, which was not well visualized and rather defective when using TOF-MRA. While a segment of the proximal marker composed of stainless steel was poorly visualized, the other parts of the parent artery and the arteries of bifurcation, including the aneurysmal neck, were clearly visualized, equivalent to that of DSA. CONCLUSIONS: UTE-MRA achieves better visualization of cerebral aneurysms after PulseRider treatment than TOF-MRA.

Long-Term Characteristics of De Novo Bleb Formation at the Aneurysm Neck After Coil Embolization in Unruptured Cerebral Aneurysms.

OBJECTIVE: De novo bleb formation at the aneurysm neck after coil embolization of unruptured intracranial aneurysms is a rarely observed type of recurrence. The aim of this study was to elucidate the clinical characteristics of recurrent aneurysms in the long-term period. METHODS: Between January 2002 and December 2015, 290 unruptured intracranial aneurysms were treated with coil embolization at our institution. Patients who underwent retreatment due to aneurysm recurrence were divided into 2 patterns of recanalization: de novo bleb formation at the neck of a coiled sac (type DNV) and an enlarged residual cavity without de novo bleb formation (type non-DNV). RESULTS: Twenty-seven patients with aneurysms (9.3%) underwent retreatment (type DNV, 7; type non-DNV, 20). The initial aneurysm size of type DNV aneurysms was significantly smaller than that of type non-DNV (6.1 ± 2.2 mm vs. 10.1 ± 3.6 mm; P < 0.01), and time to retreatment in type DNV was significantly longer than that in type non-DNV (9.4 ± 5.3 years vs. 2.0 ± 2.0 years; P < 0.01). Two type DNV basilar artery (BA) aneurysms ruptured after a few years; however, the other type DNV aneurysms, including 4 anterior circulation aneurysms (including the internal carotid artery), were observed to grow gradually without rupture for >10 years until retreatment. CONCLUSIONS: De novo bleb formation at the neck of a coiled sac emerges with insidious growth during long-term follow-up. Constant caution should be exercised, even in cases of small- and medium-sized anterior circulation aneurysms. A risk of rupture risk may be anticipated, especially in BA lesions.

Hemodynamic features of an intracranial aneurysm rupture predicted by perianeurysmal edema: A case report.

BACKGROUND: Perianeurysmal edema (PAE) has been suggested as an indicator of potential aneurysm rupture; however, the hemodynamic features of these aneurysms are still unknown. A computational fluid dynamic (CFD) analysis was performed to evaluate the hemodynamic features of a very rare case of a ruptured middle cerebral artery (MCA) aneurysm with PAE. CASE DESCRIPTION: A 65-year-old woman presented with disturbed consciousness. A subarachnoid hemorrhage due to an azygos anterior cerebral artery (ACA) aneurysm rupture was suspected. An unruptured MCA aneurysm with PAE was identified in the left temporal lobe. Although the ACA aneurysm was clipped to prevent re-bleeding, the MCA aneurysm subsequently ruptured 6 days later. Clipping of the MCA aneurysm was performed, and hemosiderin deposits suggestive of sentinel bleeding were found on the surface of the aneurysm dome. CFD analysis revealed unstable hemodynamic stress at the expanded bleb area after rupture, localized to the rupture site. Moreover, this analysis revealed flow impingement with pressure elevation and low wall shear stress, which indicated increased inflammation and aneurysm wall thinning that likely led to rupture. CONCLUSION: Hemosiderin deposits at the aneurysm wall and PAE indicates leakage from a cerebral aneurysm. Hemodynamic stress at the aneurysm may promote an inflammatory response and lead to wall weakening accompanied by PAE. Based on our findings, we recommend that surgical intervention should be considered as the first line of treatment for such aneurysms to prevent rupture.

Delayed Bleeding of Unruptured Intracranial Aneurysms After Coil Embolization: A Retrospective Case Series.

OBJECTIVE: Delayed bleeding of unruptured intracranial aneurysms (UIAs) after coil embolization is rare; this study aimed to analyze the occurrence of delayed bleeding of UIAs after coil embolization. METHODS: We retrospectively analyzed patients with UIAs after coil embolization between January 2002 and December 2018 and assessed the features of UIAs with delayed bleeding after coil embolization. RESULTS: Analysis included 307 patients with 335 UIAs. Mean follow-up was 7.1 ± 4.9 years, and total follow-up was 2365 aneurysm-years. There were 271 (80.9%) aneurysms located in the anterior circulation and 64 (19.1%) aneurysms located in the posterior circulation. Significant differences were observed between the 2 groups in terms of maximum size of the aneurysm (P < 0.01), width of the aneurysm neck (P < 0.01), and number of retreatment cases (P < 0.01). During the follow-up period, delayed bleeding occurred in 4 aneurysms (annual bleeding rate of 0.17%); all were located in the posterior circulation. The original size was not relatively large (mean 8.6 ± 2.4 mm). All aneurysms bled within 5 years (mean 35 ± 9.6 months) after the initial treatment. Two were de novo aneurysms that developed adjacent to the coiled aneurysms and were not detected on follow-up magnetic resonance angiography. CONCLUSIONS: Cautious follow-up of UIAs with digital subtraction angiography is important, articularly within the first 5 years after the procedure. If there are changes in the anatomic outcomes, short-term reassessment or additional treatment should be actively considered, particularly for aneurysms in the posterior circulation.

Development and natural course of lateral posterior choroidal artery aneurysms arising from fragile choroidal collaterals in moyamoya disease: illustrative cases.

BACKGROUND: Choroidal collaterals are a risk factor for hemorrhagic stroke, even in the nonhemorrhagic hemisphere, among patients with moyamoya disease (MMD). Peripheral choroidal aneurysms rupture in fragile collaterals; however, the development and natural course of these aneurysms remain elusive. OBSERVATIONS: A 51-year-old woman, who had experienced a right cerebral hemorrhage 3 years earlier, presented with asymptomatic minor bleeding from a left lateral choroidal artery aneurysm in a predeveloped choroidal anastomosis. Although the aneurysm spontaneously thrombosed within 2 months, the choroidal collaterals persisted. After bypass surgery, the choroidal anastomosis regressed, and neither a de novo aneurysm nor a hemorrhagic stroke occurred. A 75-year-old woman with MMD, who had experienced a left frontal infarction 6 years earlier, experienced recurrent right intraventricular hemorrhage from a ruptured lateral choroidal artery aneurysm that developed in the choroidal anastomosis. The aneurysm spontaneously regressed 3 days after the rebleeding with no recurrence over the following 7 years. LESSONS: Choroidal artery aneurysms may develop in the choroidal anastomosis and rupture in the nonsurgical or contralateral hemispheres. Patients with MMD who have a history of hemorrhagic or ischemic stroke and impaired cerebral blood flow require careful observation. Although aneurysms may rapidly regress spontaneously, bypass surgery can stabilize hemodynamic stress and prevent further hemorrhage.

Retrograde T-Stent Technique for Large, Wide-Necked Internal Carotid-Posterior Communicating Artery Aneurysm.

Objective: We report a case of a wide-necked internal carotid-posterior communicating (IC-Pcom) artery aneurysm treated by the retrograde T-stent technique in which a stent was also placed in the Pcom artery via the posterior circulation. Case Presentation: A 35-year-old woman was diagnosed with an unruptured right IC-Pcom artery aneurysm (maximum diameter: 11 mm, neck diameter: 8.5 mm) during a detailed examination for vertigo. The Pcom artery (2.1 mm) branched from the aneurysmal dome. A microcatheter was guided in retrograde via the Pcom artery from the posterior circulation. A low-profile visualized intraluminal support (LVIS) Jr. 2.5 mm × 17 mm was deployed from the internal carotid artery (ICA) to the Pcom artery, and then, an LVIS 4.5 mm × 23 mm was deployed while pressing the flare of the LVIS Jr. protruding into the ICA. T configuration stenting was completed, and the coil was inserted as tightly as possible. Conclusion: The retrograde T-stent technique, which has the advantage of optimal stent positioning, is useful for preserving a Pcom artery branching from the aneurysmal dome.

Unilateral oculomotor nerve palsy caused by arterial compression accompanying subarachnoid hemorrhage: a case report.

Unilateral oculomotor nerve palsy, often caused by aneurysmal compression, is one of the decisive findings for confirming the site of a ruptured aneurysm. However, arterial compression can also cause unilateral oculomotor nerve palsy. Here, we present the case of a 59-year-old woman with a ruptured right internal carotid-posterior communicating artery aneurysm accompanied by contralateral oculomotor nerve palsy. The nerve was found to be compressed by the posterior cerebral artery and was isolated from the ruptured aneurysm. When confirming a ruptured aneurysm based on the evidence of unilateral oculomotor palsy, the arteries surrounding the nerve must be thoroughly assessed.

Safety and feasibility of the distal transradial approach: A novel technique for diagnostic cerebral angiography.

PURPOSE: We aimed to evaluate the safety and feasibility of the distal transradial approach (DTRA) as a novel technique for cerebral angiography based on our institutional initial experience. METHODS: We retrospectively analyzed our institutional database of consecutive diagnostic cerebral angiographies performed with DTRA from December 2018 to August 2019. Patient demographics and clinical and procedural data were recorded. RESULTS: In total, 51 diagnostic cerebral angiographies in 51 patients (age, 15-83 years; mean age, 59.4 years, SD 13.5; 35 (69%) females) were performed or attempted with DTRA. Ultrasound evaluation showed that the mean inner distal radial artery diameter was significantly smaller than the mean inner forearm radial artery diameter (2.19 mm vs. 2.56 mm, P < 0.001). Cannulation via the distal radial artery was successful in 47 (92%) procedures. In the four procedures that failed, operators converted to the ipsilateral transradial approach without repositioning or redraping. Selective catheterization of the intended vessel was achieved in 64 (91%) of 70 vessels. In the remaining six, operators achieved the objective of the examination with angiography injecting from proximal and conversion to another approach was not required. One patient experienced temporary numbness around the puncture site after the procedure. No radial artery occlusion was identified in the patients who underwent ultrasound evaluation. CONCLUSION: Our results demonstrate that DTRA could become a standard approach for diagnostic cerebral angiography owing to the low complication rate and the high cannulation success rate.

Treatment Strategies for Infectious Intracranial Aneurysms: Report of Three Cases and Review of the Literature.

We retrospectively reviewed the cases of three patients with infectious intracranial aneurysms (IIAs), and discuss the indications for surgical and endovascular treatments. We treated two men and one woman with a total of six aneurysms. The mean age was 43.3 years, ranging from 36 to 51 years. One patient presented initially with an intraparenchymal hemorrhage, one with mass effect, and the other one had four aneurysms (one causing subarachnoid hemorrhages and the other causing delayed intraparenchymal hemorrhages). The average size of all aneurysms was 12.2 mm (range, 2-50 mm). They were preferentially located in the distal posterior cerebral artery, and then, in the middle cerebral artery. All cases were caused by infective endocarditis. We selected endovascular treatments for five aneurysms and treated all but one within 24 h from detection. One aneurysm was treated by combined therapy with endovascular intervention and surgery. After treatment, none of the IIAs presented angiographical recurrence or re-bleeding. If feasible, endovascular treatment is probably the first choice, but a combined surgical and endovascular approach should be considered if surgery or endovascular treatment alone are not feasible. The method of treatment should be individualized. For cases with high risk of aneurysm rupture, treatment should be performed as soon as possible.