Cytotoxic Lesions of the Corpus Callosum Associated with Aneurysmal Subarachnoid Hemorrhage May Influence Shunt-Dependent Chronic Hydrocephalus.

BACKGROUND: Cytotoxic lesions of the corpus callosum (CLOCCs) are occasionally associated with aneurysmal subarachnoid hemorrhage (aSAH). The effects of aSAH on clinical outcomes in such cases are unclear. The present study aimed to investigate the frequency and characteristics of CLOCCs associated with aSAH to ascertain the predictors of shunt-dependent chronic hydrocephalus (SDCH) after aSAH. METHODS: We retrospectively investigated cases of aSAH treated by coil embolization. Patients were divided into those with and without CLOCCs. Between-group differences were evaluated, including clinical outcomes and the characteristics of both the patients and the aneurysms. Patients were divided into those with and without SDCH to identify predictive factors of SDCH after aSAH focusing on CLOCCs. RESULTS: This single-center study included 196 patients with aSAH. All patients received coil embolization between April 2013 and March 2020. CLOCCs were detected in 38 (19.4%) patients. In the group with CLOCCs, male sex, poor severity grade at onset, acute hydrocephalus, SDCH (all P < 0.01), and Fisher group 3 or 4 (P = 0.04) were significantly more common than in the group without CLOCCs. Diabetes and CLOCCs were significant predictors of SDCH after aSAH in multivariate analysis (diabetes: P < 0.01, odds ratio: 6.73, 95% confidence interval: 1.61-28.09; CLOCCs: P < 0.01, odds ratio: 6.86, 95% confidence interval: 2.87-16.38). CONCLUSIONS: CLOCCs and SDCH were common in patients with poor-grade aSAH, and CLOCCs were independent predictors of SDCH after aSAH. Meticulous follow-up is necessary to detect SDCH after aSAH, especially in patients with poor-grade aSAH and CLOCCs.

Influence of size ratio on retreatment after coil embolization for unruptured bifurcation aneurysms.

Background: Aneurysm size is considered a risk factor for aneurysm rupture, and even small aneurysms may rupture, especially bifurcation aneurysms (BAs), which are occasionally detected. Therefore, we aimed to investigate the predictors of retreatment after coil embolization for unruptured BAs, with a particular focus on the absolute and relative size of the aneurysm (size ratio [SR]). Methods: To evaluate the predictors of retreatment, patients were divided into two groups: those with and those without retreatment. Patient characteristics and radiographic assessments were compared between the groups. SR was defined as the ratio of the maximum aneurysm diameter and the average diameter of the parent artery. Results: Overall, 181 unruptured BAs in 176 patients were investigated. The mean age of the patients was 63.8 ± 9.6 years. The mean aneurysm size and SR were 7.18 ± 2.94 mm and 2.49 ± 1.32, respectively. Further, 12 aneurysms with retreatment (6.6 %) and 169 aneurysms without retreatment were compared. In univariate analysis, SR was significantly higher in the group with retreatment (P = 0.02), but aneurysm size was not significantly different between the groups (P = 0.09). Multivariable analysis revealed that SR > 2.6 was a significant predictor of retreatment (P = 0.03; odds ratio: 10.41; 95 % confidence interval: 2.1-51.73). Conclusions: This study showed that SR influences retreatment after coil embolization for unruptured BAs. Therefore, if the aneurysm size and parent artery diameter were small, as in cases with a large SR, meticulous follow-up after coil embolization is required to detect recurrence and recanalization.

Impact of size ratio on thromboembolic events based on diffusion-weighted imaging after coil embolization for unruptured basilar apex aneurysm.

PURPOSE: Coil embolization is one of the main endovascular treatment for basilar apex aneurysms (BAAs), and thromboembolic events are important complications of coil embolization. Even in small aneurysms, there is a risk of rupture, and aggressive treatment should be considered for unruptured BAAs. Using diffusion-weighted imaging (DWI), the study aimed to investigate thromboembolic events after coil embolization for unruptured BAAs by focusing on the absolute aneurysm size and relative aneurysm size (size ratio [SR]). METHODS: To evaluate the predictors of thromboembolic events, patients were divided into those with and without hyperintensity on DWI after coil embolization. Patient and radiographic characteristics were compared between the two groups. SR was defined as the maximum aneurysm diameter divided by the average parent artery diameter. RESULTS: Fifty-six unruptured BAAs in 56 patients were investigated. The mean aneurysm size and SR were 7.61 ± 2.18 mm and 2.74 ± 1.45, respectively. Postprocedural hyperintensity on DWI was detected in 17 patients (30.4%). SR was significantly larger in the group with hyperintensity on DWI (3.75 ± 1.97 vs. 2.3 ± 0.82, P < 0.01) in the univariate analysis. Multivariate analysis revealed that SR> 3.0 was a significant predictor of thromboembolic events after coil embolization for unruptured BAAs (odds ratio: 12.15; 95% confidence interval: 2.95-49.98; P < 0.01). CONCLUSIONS: This study showed that SR is a predictor of thromboembolic events after coil embolization for unruptured BAAs. Therefore, if even in small BAAs, if the BAAs dome height is large compared to the diameter of the posterior cerebral artery (e.g., there is a large SR), preoperative evaluation of the use of antiplatelet therapy is important, particularly to prevent thromboembolic events.

A case of cribriform plate dural arteriovenous fistulas with a rare complication after endovascular therapy.

Background: Cribriform plate dural arteriovenous fistulas (dAVFs) are rarely encountered. Here, we report a case of cribriform plate dAVF with a rare complication after endovascular therapy. Case Description: A 60-year-old man presented with severe sudden headache. Head computed tomography showed right subdural hematoma, and magnetic resonance angiography showed dilated bilateral frontal cortical vein. Digital subtraction angiography revealed cribriform plate dAVF fed by the anterior and posterior ethmoidal branches of the bilateral ophthalmic arteries. Transarterial embolization with liquid embolic material was performed and the fistula disappeared. Although magnetic resonance imaging showed the disappearance of the cribriform plate dAVF and subdural hematoma, the patient complained of anosmia after the procedure. Conclusion: Endovascular embolization is an effective treatment option for treating cribriform plate dAVFs. However, anosmia is a possible complication, and endovascular surgeons should take care of this complication, especially in cribriform plate dAVFs supplied with blood bilaterally.

Global outflow angle influences silent ischemic events in coil embolization for unruptured distal anterior cerebral artery aneurysms.

BACKGROUND: Distal anterior cerebral artery (DACA) aneurysms are rare, and endovascular treatment of these aneurysms is challenging. Thromboembolic events, including silent ischemic events, are one of the most important complications of coil embolization for cerebral aneurysms. The treatment outcomes and predictors of silent ischemic events in coil embolization for unruptured DACA aneurysms were investigated, focusing on the morphological characteristics of aneurysms, especially the inflow angle (IA) and global outflow angle (GOA). METHODS: A total of 12 patients with 12 unruptured DACA aneurysms, treated with coil embolization at our institute, were retrospectively investigated. Predictors for silent ischemic events were evaluated by comparing diffusion-weighted imaging (DWI)-positive and DWI-negative patients. RESULTS: Silent ischemic events detected on DWI were observed in eight aneurysms (66.7%). Comparison of the morphological characteristics of aneurysms between the two groups showed a significantly smaller GOA in the DWI-positive group than in the DWI-negative group (172.6 ± 17.7° vs. 216.8 ± 16.8°, P < 0.01). A multivariate analysis showed that GOA <195° was a significant predictor of silent ischemic events (P = 0.04; odds ratio: 23.62; 95% confidence interval: 1.11-490.39). CONCLUSION: A small GOA was a significant predictor of silent ischemic events after coil embolization for unruptured DACA aneurysms. While some patients can be treated safely with minimally invasive coil embolization, it is necessary to consider surgical clipping in patients at high risk of thromboembolic events with coil embolization.

Outflow angle: a risk factor for thromboembolic complications in coil embolisation for treating unruptured middle cerebral artery bifurcation aneurysms.

BACKGROUND: Thromboembolic complications are a relevant risk in coil embolisation of cerebral aneurysms. This retrospective study aimed to assess the treatment outcomes of unruptured middle cerebral artery (MCA) bifurcation aneurysms and the predictors for thromboembolic complications based on the aneurysm morphological characteristics. We examined the following three features: inflow angle, outflow angle (OA), and bifurcation angle, formed by the aneurysm and neighbouring blood vessels. METHODS: A total of 32 MCA bifurcation aneurysms were retrospectively investigated in 32 patients treated consecutively at our institute between April 2008 and March 2019. The predictors for thromboembolic complications were analysed in two groups: patients with and without thromboembolic complications. RESULTS: Perioperative thromboembolic complications were detected in six patients (18.8%), including two and six intra- and post-procedural thromboembolic complications, respectively; all cases were resolved. Regarding the aneurysms' morphological characteristics, the group with thromboembolic complications showed a significantly smaller OA (55.58° ± 14.05° vs. 86.04° ± 28.58°, P = 0.01) than the group without complications. Multivariate analysis revealed that smoking habits and OA < 70° were significant predictors of thromboembolic complications (smoking habits: P = 0.01, odds ratio [OR]: 6.89, 95% confidence interval [CI]: 3.78-12.62; OA < 70°: P = 0.04, OR: 3.19, 95% CI: 1.52-6.56). CONCLUSIONS: Our findings indicate significant pre-procedural predictors of thromboembolic complications to consider for safe treatment; clipping should be preferred to coil embolisation in high-risk patients. The method of choice should be considered in each case to allow the safe treatment of unruptured MCA aneurysms.

Skull shape abnormalities in ischemic cerebrovascular and mental diseases in adults.

Morphological changes in the child skull due to mechanical and metabolic stimulation and synostosis of the suture are well known. On the other hand, few studies have focused on clinical conditions relevant for adult skull deformity. We retrospectively reviewed computed tomography (CT) findings obtained from 365 cases that were treated for head injuries, moyamoya disease, cervical internal carotid artery stenosis, and mental diseases, and investigated the morphological changes in the skull associated with these diseases. The findings from head injuries were used not only for control subjects, but also for the analysis of generational changes in skull shape based on birth year. Head shape had a brachiocephalic tendency with occipital flattening in people born from the 1950s onwards. Cases of moyamoya disease, cervical internal carotid artery stenosis, and mental diseases showed significantly thicker frontal and occipital bone than those of control subjects. The skull thickening was especially noticeable in the frontal bone in moyamoya disease. Plagiocephaly was significantly frequent in moyamoya disease. These uncommon skull shapes are useful CT findings in screening subjects for early evidence of mental diseases and intracranial ischemic diseases with arterial stenosis.

Target Coil Embolization Using the Combined Transarterial and Transvenous Balloon-assisted Technique for Traumatic Direct Carotid Cavernous Fistula.

Herein, we describe a case of traumatic direct carotid cavernous fistula (DCCF) treated with target coil embolization using the combined transarterial and transvenous balloon-assisted technique. The patient was a 59-year-old woman who had been involved in a vehicular accident. She was admitted to the hospital due to chemosis and exophthalmos. Cerebral angiography revealed a shunt from the internal carotid artery (ICA) to the cavernous sinus (CS), which indicated DCCF. Thus, target coil embolization using the combined transarterial and transvenous balloon-assisted technique was performed. Angiography was performed 1 week after surgery to confirm the disappearance of DCCF. No recurrence was observed during the 1-year follow-up after treatment. Thus, target coil embolization using the combined transarterial and transvenous balloon-assisted technique is safe and effective for the treatment of traumatic DCCF.

Predictors of Clopidogrel Hyper-Responsiveness in Neuro-Interventional Procedures.

BACKGROUND: Hyper-responsiveness to clopidogrel abnormally inhibits platelet aggregation and increases hemorrhagic complications. The present study investigated clinical factors related to clopidogrel hyper-responsiveness in neuro-interventional procedures. METHODS: Two hundred twenty-four patients receiving clopidogrel for coil embolization to treat unruptured cerebral aneurysm or carotid artery stenting to treat carotid artery stenosis at the internal carotid artery origin were retrospectively reviewed for their P2Y12 reactivity unit (PRU) values and clinical characteristics. Hyper-responsiveness to clopidogrel was defined as a PRU of <95. RESULTS: The mean PRU was 218.2 ± 77.8. Hyper-responsiveness to clopidogrel was observed in 12 patients (5.4%). Hyper-responsiveness was observed in younger patients, patients with a lower concentration of hemoglobin A1c, and patients with a higher low-density lipoprotein cholesterol (LDL-C) concentration compared with non-hyper-responsive patients (P = 0.01, P < 0.01, P < 0.01, respectively). On analysis of concomitant drugs, the patients in the hyper-responsive group were less frequently administered calcium channel blockers (CCBs) compared with the non-hyper-responsive group (P = 0.01). No significant differences in the usage of proton pump inhibitors or statins were observed. A LDL-C concentration of >120 mg/dL and no usage of CCBs were significant independent predictors of hyper-responsiveness to clopidogrel with a multivariate analysis (OR; 6.16, 95% CI, 1.57-26.64, P = 0.01, OR; 0.09, 95% CI, 0.01-0.82, P = 0.03, respectively). CONCLUSION: The present study shows that a higher LDL-C concentration and no usage of CCBs are independent predictors of clopidogrel hyper-responsiveness. These results are useful to predict perioperative hemorrhagic complications. Considering dose reduction of clopidogrel or alternative drugs in high risk cases is necessary to prevent perioperative hemorrhagic complications.

High HMGA2 expression without gene rearrangement in meningiomas.

High mobility group AT-hook 2 (HMGA2) is a non-histone transcriptional regulator protein. Aberrant expression of the HMGA2 gene (HMGA2) and structural rearrangement at the chromosomal region 12q14 with HMGA2 involvement have been reported in several mesenchymal tumors. We analyzed truncated and full-length HMGA2 expression in 55 cases of meningioma, the most common brain tumor of mesenchymal origin. Fluorescence in situ hybridization and 3'-rapid amplification of cDNA ends were used to investigate the possibility of gene rearrangements. Moreover, the relationship between HMGA2 expression and clinicopathological features was assessed. Compared with normal brain tissues, 95% of the meningioma tissues exhibited increased HMGA2 expression. In 14 cases, the expression of truncated HMGA2 was more than two-fold higher than that of paired full-length HMGA2. Chromosomal translocation involving the chromosomal region 12q14 was undetectable. No significant correlation was found between the Ki-67 labeling index and HMGA2 expression and between the HMGA2 expression and the clinicopathological features. The majority of the meningioma cases displayed increased HMGA2 expression, which was not attributed to the chromosomal rearrangement at the corresponding region. Similar to that in the other mesenchymal tumors, increased HMGA2 expression was not associated with tumor cell proliferation in meningiomas.

[Spontaneous Retroclival Subdural Hematoma Diagnosed Using Magnetic Resonance Imaging in an Adult Patient:A Case Report].

Spontaneous retroclival subdural hematoma is rare among adults. To the best of our knowledge, only six cases have been reported. A 73-year-old man presented with sudden severe headache, diplopia, and dysarthria, with no history of trauma. Head CT revealed a retrociliary hematoma. No obvious causes of bleeding, such as cerebral aneurysms or malformations, were detected. Conservative treatment was provided to the patient. MRI showed an intraventricular hemorrhage and a space between the basilar artery and hematoma three days after onset. The hematoma almost disappeared on day 7. MRI, particularly T2-weighted sagittal MRI, is effective in localizing hematomas and confirming intraventricular hemorrhages.

Rare clinical presentations of pleomorphic xanthoastrocytoma with a high proliferative index: Two case reports.

INTRODUCTION: Pleomorphic xanthoastrocytomas (PXA) are rare, typically benign, slow-growing tumors that commonly occur in the cerebral hemispheres. We describe two cases of clinically aggressive PXA with uncommon locations; one was in the tectal plate, and the other had simultaneous multicentric lesions. PATIENT CONCERNS: The both cases presented with severe headache with no significant past medical history. DIAGNOSIS: PXA World Health Organization grade II were histopathologically diagnosed from surgically resected specimens, and immunohistochemical and sequence analysis revealed a high Ki-67 proliferative index and BRAF V600E mutation in both the cases. INTERVENTIONS: The first case presented with multicentric lesions and underwent partial resection, whereas the second case presented with a tectal plate tumor that was managed by gross total surgical resection. Strong 5-aminolevulinic acid (5-ALA)-induced fluorescence was observed in both the lesions. Postoperative radiotherapy plus concomitant and adjuvant temozolomide was administered to both the patients. OUTCOMES: Despite completing adjuvant chemo-radiotherapy, both the patients had local tumor recurrence at 2 and 5 months after the operation, respectively. CONCLUSION: The progressive clinical courses in our cases suggest that additional postoperative therapy should be considered during the treatment of PXA with a high Ki67 index, and that temozolomide with radiotherapy, followed by temozolomide maintenance therapy, may not prevent recurrence in such tumors. Importantly, our experience implies that unlike other subtypes of low grade gliomas, 5-ALA fluorescence is useful for intraoperative visualization of PXA.

A Patient with a Ruptured Blood Blister-like Aneurysm of the Internal Carotid Artery in Whom Two LVIS Stents Were Inserted.

Objective: We report a case in which multiple overlapping low-profile visualized intraluminal support (LVIS) stents were used as monotherapy for ruptured blood blister-like aneurysm (BBA) of the internal carotid artery (ICA). Case Presentation: A 48-year-old female presented to the emergency room with acute-onset headache. She was alert without neurological deficit with subarachnoid hemorrhage (SAH) Hunt and Kosnik grade I. Emergency angiography revealed a BBA from the supraclinoid ICA. This aneurysm had a small diameter, which makes coil embolization difficult. Therefore, we planned to use multiple overlapping LVIS stents as monotherapy for the ruptured aneurysm. The postoperative course was uneventful without rebleeding. The patient exhibited no neurological deficits on the clinical follow-up at 1 year. Conclusion: Multiple overlapping LVIS stents as monotherapy is useful for ruptured BBAs of the ICA.

A Patient with an Unruptured Aneurysm in the Internal Carotid Artery-duplicated Middle Cerebral Artery on Whom Coil Embolization with Balloon Remodeling Was Performed.

Objective: Treatment of an unruptured aneurysm at the origin of duplicated middle cerebral artery (DMCA) by coil embolization using balloon remodeling has not been reported. We report a case of coil embolization using balloon remodeling for an unruptured aneurysm at the origin of DMCA. Case Presentation: A 71-year-old female was found to have an unruptured aneurysm at the origin of DMCA during an examination for headache. Coil embolization using balloon remodeling for the wide neck aneurysm to preserve both the internal carotid artery (ICA) and DMCA was successful. The perioperative course was uneventful. Conclusion: This treatment enables complete embolization, and preserves both the ICA and DMCA. Thus, it is useful for aneurysms at the origin of DMCA.

Increased Twist and ZEB2 expression in a cutaneous metastasis of high-grade glioma.

Extra-central nervous system metastasis of gliomas is extremely rare, and the biological mechanism underlying it remains poorly understood. Epithelial-to-mesenchymal transition (EMT) has received attention as one of the important processes of cancer metastasis. Here we describe the case of a 32-year-old man with cutaneous metastasis of high-grade glioma, together with the analysis of EMT-related molecules. Our patient presented with a high-grade glioma in the right frontal lobe. Cutaneous metastasis under the surgical scar developed 17 months after complete resection of the intracranial tumor. Histopathology of both the original and metastatic tumors revealed hypercellularity; the tumors predominantly comprised glial tumor cells with poor cellular processes. Immunohistochemical analysis demonstrated intense expression of nestin, focal expression of glial fibrillary acid protein, and absence of expression of oligodendrocyte transcription factor 2, endothelial membrane antigen, or neurofilament. Genetic analyses could not provide definitive diagnostic information of glioma subtypes. Immunohistochemical analysis for EMT-related biomarkers demonstrated increased Twist, zinc finger E-box-binding homeobox 2 (ZEB2), matrix metalloproteinase 2 (MMP2), and MMP9 expressions in tumor cells of the metastatic lesion compared with those of the primary lesion. Slug, E-cadherin, and N-cadherin expression were absent in both primary and metastatic lesions; however, ZEB1 expression was present in both. Our results suggest that Twist, ZEB2, MMP2, and MMP9 facilitate cutaneous metastasis of gliomas.

Clinical relevance of BRAF status in glial and glioneuronal tumors: A systematic review.

Alterations in the BRAF gene have been reported to play a key role in the tumorigenesis of various tumors. Recent studies have shown the existence of BRAF alterations in ganglioglioma (GG), pilocytic astrocytoma (PA), pleomorphic xanthoastrocytomas (PXA), and epithelioid glioblastoma (eGBM). The focus of this review was the association between the clinical characteristics and BRAF status in these glial and glioneuronal tumors. The BRAF abnormalities, KIAA1549-BRAF fusion and BRAF mutation, were detected in approximately 50% of the analyzed tumors regardless of the tumor location, and there were site-specific BRAF abnormalities that became more remarkable on analysis by each tumor subtype. The median age of patients with KIAA1549-BRAF fusion was much lesser than that of those with BRAF mutations. Histological analysis indicates that the existence of KIAA1549-BRAF fusion is related to pilocytic morphology. The review of imaging features indicated that cyst formation is associated with the existence of KIAA1549-BRAF fusion in PA and GG and the lack of BRAF mutation in GG. Hemorrhage was significantly present in cases of GG with KIAA1549-BRAF fusion, but no relevance was shown in cases with BRAF mutations. No significant relevance was detected between the presence of calcification and BRAF alterations. Our clinical and genetic review of BRAF-related tumors indicated that the KIAA1549-BRAF fusion was strongly associated with PA, but not with other glial and glioneuronal tumors.

Intracranial endodermal cyst presenting with nonobstructive hydrocephalus: A case report.

RATIONALE: Endodermal cysts are rare benign lesions in the central nervous system. Their common symptoms include headache and neck pain caused by mass effect or inflammatory reaction. We report the case of an elderly woman with intracranial endodermal cyst who presented with nonobstructive hydrocephalus. PATIENT CONCERNS: A 78-year-old woman presented with acute deterioration of consciousness caused by acute hydrocephalus. She subsequently underwent ventriculoperitoneal shunt placement. Eighteen months after this operation, she developed numbness of extremities and gait and progressive cognitive disturbances. DIAGNOSIS: Initially, the endodermal cyst could not be recognized, but it became clinically evident in the craniocervical junction after ventriculoperitoneal shunt placement. MRI revealed multiple cystic lesions in the pontomedullary cistern. Postoperative pathology confirmed the diagnosis of endodermal cyst. INTERVENTIONS: Subtotal resection of the cystic lesion was performed. Intra-operatively, multiple cysts containing a milky white fluid were noted and the medullary surface including the median and lateral apertures of the fourth ventricle were covered by thick, cloudy arachnoid membrane. OUTCOMES: Although the numbness of extremities improved after the surgery, she remained bedridden due to deterioration in cognitive function and generalized muscle weakness. The patient developed recurrence 2 months after the surgery; however, no additional surgery was performed owing to her poor general condition. LESSONS: Endodermal cysts rarely present with nonobstructive hydrocephalus caused by recurrent meningitis. In such cases, the lesions are often invisible on initial diagnostic imaging, and complete resection of the lesions is typically difficult because of strong adhesion between the cyst walls and contiguous vital structures.

Carotid surgical cut-down technique for neuroendovascular therapy.

BACKGROUND: Neuroendovascular therapy is typically performed via the femoral artery, but there are rare cases in which a tortuous upstream angioarchitecture makes it difficult to access the intracranial circulation via this route. METHODS: In this case series, we describe six cases treated by surgical cut-down in the neck, with puncture of the carotid artery. Antiplatelet and anticoagulation agents were used in all cases. The indications for the technique were postsurgical thoracic aortic aneurysm (two cases), postsurgical abdominal aortic aneurysm (one case), major vessel tortuosity of the common carotid artery (two cases) and aortic arch anomaly (one case). RESULTS: The surgical cut-down technique permitted successful neuroendovascular therapy. Although one patient had a small cervical haematoma, he was treated without surgical evacuation. CONCLUSION: Overall, our findings indicate that the surgical cut-down technique is safe and useful for patients in whom the femoral approach is unsuitable.

Microhemorrhagic transformation of ischemic lesions on T2*-weighted magnetic resonance imaging after Pipeline embolization device treatment.

OBJECTIVEThe authors sought to demonstrate that hemorrhagic transformation of ischemic lesions is the main cause of delayed intracerebral hemorrhage (ICH) after Pipeline embolization device (PED) treatment and to estimate the rate of hemorrhagic transformation of new postprocedure ischemic lesions.METHODSPatients who underwent PED placement (PED group) from November 2015 to March 2017 or stent-mediated embolization (EN group) from December 2010 to October 2015 were retrospectively analyzed. Pre- and postprocedural MR images and 6-month follow-up MR images for each patient were scored for the presence of postprocedural bland ischemic and hemorrhagic lesions using diffusion-weighted MRI (DWI) and T2*-weighted MRI (T2*WI), respectively.RESULTSThe PED group comprised 28 patients with 30 intracranial aneurysms, and the EN group comprised 24 patients with 27 intracranial aneurysms. The mean number of ischemic lesions on DWI 1 day postprocedure was higher in the PED group than in the EN group (5.2 vs 2.7, p = 0.0010). The mean number of microbleeds detected on T2*WI 6 months postprocedure was higher in the PED group than in the EN group (0.6 vs 0.15, p = 0.028). A total of 36.7% of PED-treated patients exhibited new microbleeds on T2*WI at 6 months postprocedure, with at least 77.8% of these lesions representing hemorrhagic transformations of the new ischemic lesions observed on day 1 postprocedure. The rate of adjunctive coil embolization (27.3% vs 0.0%, p = 0.016) and the mean number of ischemic lesions observed 1 day postprocedure (6.6 vs 4.3, p = 0.020) were predictors of subsequent microbleeds in the PED group.CONCLUSIONSNew microbleeds detected using T2*WI at 6 months postprocedure were more common after PED treatment than after stent-mediated embolization. Approximately three-quarters of these lesions were hemorrhagic transformations of new ischemic lesions observed on day 1 postprocedure. Prevention of intraprocedural or postprocedural infarcts is necessary to reduce the risk of hemorrhagic complications following PED placement.

Delayed Posttreatment Residual Flow into Aneurysm After Flow Diverter Placement.

BACKGROUND: Inflow into an aneurysm sac immediately following flow diverter (FD) treatment is an assumed cause of delayed aneurysmal rupture. The significance of delayed posttreatment residual flow occurring months after FD treatment is unknown. CASE DESCRIPTION: A 76-year-old woman with a large intracranial aneurysm measuring 23.0 × 18.1 mm in the cavernous segment of the right internal carotid artery was treated with placement of a single FD (Pipeline Embolization Device, Covidien, Irvine, California, USA). Postprocedure digital subtraction angiography (DSA) demonstrated flow stagnation inside the aneurysm dome. The patient was discharged 9 days post procedure without new neurologic deficits. A 6-month follow-up DSA demonstrated delayed posttreatment residual flow into the aneurysm sac. Although she was scheduled for additional FD placement because of concern for aneurysmal rupture, the operation was not conducted due to an interim motor vehicle accident. Oral treatment with aspirin (100 mg/day) and clopidogrel (75 mg/day) was continued during her recovery. DSA performed 12 months post procedure showed that the aneurysm had completely thrombosed. CONCLUSIONS: Our findings suggest that delayed post-treatment residual flow into an aneurysm may form part of the normal clinical course post FD placement and may not preclude eventual thrombosis of the aneurysm. Larger studies are needed to determine whether more frequent follow-up DSAs after FD placement are necessary and whether all patients exhibiting delayed post-treatment residual flow into an aneurysm require additional FD placement or if watchful waiting is a more suitable course.