An analysis of the demographic history of the risk allele R4810K in RNF213 of moyamoya disease.

BACKGROUND: Ring finger protein 213 (RNF213) is a susceptibility gene of moyamoya disease (MMD). A previous case-control study and a family analysis demonstrated a strong association of the East Asian-specific variant, R4810K (rs112735431), with MMD. Our aim is to uncover evolutionary history of R4810K in East Asian populations. METHODS: The RNF213 locus of 24 MMD patients in Japan were sequenced using targeted-capture sequencing. Based on the sequence data, we conducted population genetic analysis and estimated the age of R4810K using coalescent simulation. RESULTS: The diversity of the RNF213 gene was higher in Africans than non-Africans, which can be explained by bottleneck effect of the out-of-Africa migration. Coalescent simulation showed that the risk variant was born in East Asia 14,500-5100 years ago and came to the Japanese archipelago afterward, probably in the period when the known migration based on archaeological evidences occurred. CONCLUSIONS: Although clinical data show that the symptoms varies, all sequences harboring the risk allele are almost identical with a small number of exceptions, suggesting the MMD phenotypes are unaffected by the variants of this gene and rather would be more affected by environmental factors.

[A Case of Moyamoya Disease with Postoperative Cerebral Hyperperfusion Syndrome Followed by Cerebral Infarction due to Watershed Shift].

The concept of "watershed shift"(WS)has been proposed as a cause of the ischemic complications following a superficial temporal artery-middle cerebral artery(STA-MCA)bypass operation performed for the management of moyamoya disease. Previous reports have observed that only 1.2-5.7% of the patients who underwent a bypass operation for the management of moyamoya disease developed cerebral infarction secondary to the WS phenomenon. To date, the WS phenomenon has not been objectively proven on imaging studies. We describe a 39-year-old woman who presented with right facial palsy and aphasia. Magnetic resonance imaging revealed cerebral infarction in the left frontal lobe secondary to moyamoya disease. Three days after undergoing the left STA-MCA bypass procedure, she showed deterioration in aphasia secondary to the occurrence of cerebral hyperperfusion syndrome(CHPS). Diffusion-weighted imaging(DWI)performed on postoperative day(POD)1 and 5 showed no area of high signal intensity. DWI performed on POD 8 showed an area of high signal intensity in the deep white matter of the left parietal lobe outside the range of the craniotomy. Postoperative fusion images of computed tomography angiography and DWI performed on POD 8 showed that the blood flow through the MCA from the bypass graft and that through the posterior cerebral artery crossed each other at the surface of the subcortical infarction. In the present case, the WS could be directly confirmed on imaging studies, and the cerebral infarction may have occurred secondary to WS concomitant with CHPS. Clinicians need to be aware of the WS phenomenon even after performing a direct bypass to treat adults with moyamoya disease.

Low Stroke Rate of Carotid Stenosis Under the Guideline-Oriented Medical Treatment Compared With Surgical Treatment.

Medical treatment for asymptomatic carotid artery stenosis (ACAS) has advanced recently. The outcomes of medical treatment and surgical treatment were evaluated to clarify the optimal treatment for ACAS.Patients with ACAS of ≥ 50% luminal narrowing underwent serial follow-up carotid artery ultrasonography for one year or more at the Center for Cardiovascular Disease Prevention between November 2006 and October 2013. The incidence of cardiovascular events (stroke, myocardial infarction, cardiovascular death) was examined in 64 patients (medical treatment group), and in 47 patients (surgical group) who underwent surgical treatment (carotid endarterectomy or carotid artery stenting) during this same period at the Department of Neurosurgery.Annual cardiovascular event rate was 0.91% (2/219 person-year) in the group of guideline-oriented medical treatment with an annual check-up for disease management and 5.6% (6/107 person-year) in the surgical group (log-rank P = 0.027; HR in the medical treatment group, 0.19 [medical treatment/surgical]; 95% confidence interval [CI], 0.028 to 0.87). Annual stroke event rate was 0.46% (1/219 person-year) in the medical treatment group and 4.7% (5/107 personyear) in the surgical group (log-rank P = 0.016; HR in the medical treatment group, 0.11 [medical treatment/surgical]; 95% CI, 0.0057 to 0.70). Multivariate logistic analysis showed that the surgical group was an independent variable associated with cardiovascular events (P = 0.049).Annual cardiovascular and stroke event rates were low in patients receiving medical treatment for ACAS and better than surgical treatment. The present study shows that medical treatment is an important option for ACAS.

[A Case of Cardiac Arrest Caused by Coronary Spasm Related to Induction of General Anesthesia before Carotid Endarterectomy].

Coronary vasospasm(CV)can cause severe arrhythmia and myocardial infarction(MI). Intraoperative CV is not limited to cardiac surgery alone. We report the case of a patient who experienced cardiac arrest after the induction of general anesthesia, but did not demonstrate any abnormalities on preoperative examination. The patient was a 60-year-old man with no history of ischemic heart disease, with NASCET 80% asymptomatic left internal carotid stenosis(ICS). We decided to perform carotid endarterectomy(CEA). Preoperative stress myocardial scintigraphy did not reveal decreased local uptake. General anesthesia was rapidly induced with propofol and remifentanil, and maintained with sevoflurane. Shortly before the start of CEA, systolic blood pressure dropped to 80 mmHg. Electrocardiography indicated decreased ST, followed by an increase, after which complete atrioventricular block occurred. Cardiopulmonary resuscitation was initiated immediately as the patient's pulse was not palpable;heart beat resumed quickly. CEA was canceled. CV was suspected by the test of nitrate administration to coronary artery performed afterwards. A temporary pacemaker was inserted and carotid artery stenting was performed under local anesthesia. Hence, no pacemaker was used intraoperatively and no abnormality was observed on electrocardiography. In the present case, CV in the coronary artery caused complete atrioventricular block, leading to cardiac arrest after inducing general anesthesia. For ICS treatment performed under general anesthesia, care must be taken regarding the possibility of the occurrence of CV.

Vaginal Delivery under Epidural Analgesia in Pregnant Women with a Diagnosis of Moyamoya Disease.

BACKGROUND: Moyamoya disease more commonly occurs in young people and women, so patients with this disease may experience pregnancy and delivery. Cesarean section (CS) is often chosen as the mode of delivery for these patients in Japan. No appropriate mode of delivery has yet been established for pregnant women with moyamoya disease in terms of stroke prevention. We have used vaginal delivery under epidural analgesia (EA) in such patients unless CS has been indicated for the maternal or fetal reasons. This study retrospectively analyzed our patients with moyamoya disease who gave birth to confirm the safety of vaginal delivery under EA. METHODS: Twelve consecutive patients diagnosed with moyamoya disease had 14 deliveries at our hospital between September 2004 and January 2013. The incidences of intrapartum stroke were compared between cases of vaginal delivery under EA and CS cases. RESULTS: Ten vaginal deliveries under EA and 4 elective CSs were performed. No intrapartum stroke was observed during either vaginal delivery under EA or CS. Among the patients who underwent vaginal delivery under EA, 1 parturient who experienced 2 deliveries suffered transient ischemic attack during both postpartum periods. All 14 infants were healthy without sequelae. CONCLUSIONS: Vaginal delivery under EA is an option for patients with moyamoya disease, provided that close cooperation with neurosurgeons, obstetricians, and anesthesiologists is assured.

Erratum to "Crossing double stent retriever technique for refractory terminal internal carotid artery occlusion" [Radiology Case Reports 17 (2022) 1848-1852].

[This corrects the article DOI: 10.1016/j.radcr.2022.03.023.].

Signal intensity changes for the middle cerebral artery on 3-dimensional time-of-flight magnetic resonance angiography indicate acute hemodynamic changes after carotid endarterectomy.

BACKGROUND: For 3-dimensional time-of-flight magnetic resonance angiography (3D-TOF-MRA), the signal intensity (SI) loss depends on the flow velocity. In this study, we aimed to evaluate whether 3D-TOF-MRA could be used as an alternative to single-photon emission computed tomography (SPECT) for assessing the increase in the regional cerebral blood flow (rCBF) after carotid endarterectomy (CEA). To do this, we compared the SI of the middle cerebral artery (MCA) on magnetic resonance angiography (MRA) and the rCBF on SPECT. METHODS: We enrolled 30 patients with internal carotid artery stenosis. SPECT and MRA were performed before and 3-4 days after CEA. rCBF was assessed using SPECT, and the SI of the MCA was assessed using single-slab 3D-TOF-MRA. Regions of interest were placed in the bilateral middle M1 portions of the MCA on MRA, and their mean SI was measured. The increase ratio of the rCBF on SPECT and the increase ratio of the SI of the MCA on MRA were calculated using the formula: (post-CEA ipsilateral/post-CEA contralateral)/(pre-CEA ipsilateral/pre-CEA contralateral). RESULTS: A significant correlation was observed between the increase ratio of the rCBF on SPECT and the increase ratio of the SI of the MCA on MRA (r=.894, y=.4863+.5184x, P<.001). All values obtained by MRA were greater than or equal to the SPECT values, indicating that MRA tends to overestimate the post-CEA rCBF increase. CONCLUSION: Because MRA identified increased rCBF after CEA, we recommend that patients first be screened using MRA.

Time-of-flight magnetic resonance angiography for detection of postoperative recurrence in patients with chronic subdural hematoma.

PURPOSE: Chronic subdural hematoma (CSDH) is associated with postoperative recurrence. Although various factors are involved in postoperative recurrence of CSDH, blood flow, especially in the middle meningeal artery (MMA), is considered to play an important role. We investigated whether the degree of signal intensity (SI) of the MMA on time-of-flight magnetic resonance angiography (TOF MRA) and various clinical factors are involved in recurrence of CSDH. METHODS: The maximum SI of both MMAs was measured on TOF MRA images within 1 month before or after the initial surgery. RESULTS: In total, 185 patients (20 with and 165 without recurrence of CSDH) were included in the analysis. The SI ratio and dementia were significant predictors of recurrence of CSDH (SI ratio: odds ratio [95% confidence interval (CI)] = 1.71 [1.32, 2.22], p < 0.0001; dementia: odds ratio [95% CI] = 7.41 [1.83, 30.1], p = 0.005). The estimated regression coefficients in the final model were 6.14 for the SI ratio and 1.28 for dementia. The risk score was derived according to these regression coefficients as follows: score = 5 × SI ratio + 1 (dementia: yes). With a score of 5, the predicted probability of recurrence was 2% [95% CI 0.7, 5.7], whereas with scores of 8 and 10, the probability was 43.3% [27.0, 61.1] and 89.5% [65.7, 97.5], respectively, which increased the risk of recurrence. CONCLUSION: Patients with an increased SI ratio of the affected MMA on TOF MRA who underwent surgery for CSDH were significantly more likely to experience recurrence.

Acute internal carotid artery occlusion due to dissection of the paraclinoid segment: Diagnostic usefulness of angiographic findings during stent retriever deployment.

Intracranial artery dissection is an uncommon but possible cause of ischemic stroke, and is usually diagnosed based on imaging findings such as mural hematoma and dissection flap. However, it is challenging to recognize the underlying dissection in cases of acute large vessel occlusion. In this report, we present a case of acute internal carotid artery occlusion, in which the underlying dissection of the paraclinoid segment was found during the thrombectomy procedure. Two thrombectomy procedures failed to recanalize the acute internal carotid artery occlusion without removing any clot. Angiography performed during a Trevo stent retriever deployment in the first pass showed obscure contrast defects in the stent strut with temporary flow restoration. In the next pass, the appearance of the contrast defects changed and a parallel linear contrast appeared on the outside of the vessel wall. These angiographic findings were identified as mural hematoma and dissection flap, indicating dissection of the paraclinoid as the cause of the occlusion. During antiplatelet loading and preparation of a dedicated intracranial stent, the Trevo stent retriever was left deployed again at the occlusion site to maintain the blood flow. After permanent stenting with an Enterprise stent, angiography revealed complete recanalization. The patient recovered fully after the procedure. In the present case, stent retriever deployment revealed the hallmarks of dissection on angiography, such as mural hematoma, dissection flap, and temporal morphological changes, by restoring the blood flow temporarily. Such angiographic findings can provide useful information on the occlusion characteristics and real-time feedback for optimal treatment strategy.

Crossing double stent retriever technique for refractory terminal internal carotid artery occlusion.

Mechanical thrombectomy is highly effective for the recovery of acute ischemic stroke with large vessel occlusion. However, refractory occlusions are still encountered despite the use of currently available devices. In this article, we present a case of refractory terminal internal carotid artery occlusion treated with the "crossing double stent retriever technique." Two thrombectomy procedures with the combined technique using a stent retriever and aspiration catheter failed to recanalize the terminal internal carotid artery occlusion that involved the dominant anterior cerebral artery. We then applied the crossing double stent retriever technique as a rescue technique. Two microcatheters were advanced across the occlusion: one to the anterior cerebral artery and the other to the middle cerebral artery. First, a Trevo NXT 4 mm stent retriever was deployed from the anterior cerebral artery. Next, an additional Trevo NXT 4 mm stent retriever was deployed from the middle cerebral artery, and full immediate restoration of flow was achieved on angiography. Intraprocedural radiological images showed that the 2 microcatheters traversed different pathways, and the 2 stent retrievers completely covered the entire vessel with apparent in-stent clot sign. Both stent retrievers were then pulled back together, and a hard clot was retrieved. Subsequent angiography revealed complete recanalization. The crossing double stent retriever technique seems an effective rescue technique for treating refractory terminal internal carotid artery occlusion, especially with the anatomical feature of branching of the dominant anterior cerebral artery. This technique can facilitate the device-clot-vessel interaction by engaging the clot via 2 different device pathways.

Effectiveness of interferon-beta therapy for recurrent glioblastoma: a case report.

AIMS AND BACKGROUND: Glioblastoma has a poor prognosis, with few therapeutic options if it recurs. We report a case in which we were able to inhibit the growth of a recurrent glioblastoma by weekly single-dose administration of interferon-beta. CASE REPORT: A patient with recurrent glioblastoma after radiation and chemotherapy was treated with nimustine and interferon-beta. After 2 cycles of nimustine, the patient's leukocyte, neutrophil, and platelet counts showed grade 4 toxicity according to the National Cancer Institute's Common Toxicity Criteria. The patient was treated with a weekly single dose of interferon-beta at 6 x 10(6) IU. The tumor showed no remarkable changes after 18 months, and the patient's Karnofsky performance status remained at 50%. CONCLUSIONS: The administration of interferon-beta produced long-term control in one case of glioblastoma and may be an effective therapy.

Usefulness of three-dimensional fast imaging employing steady-state acquisition MRI of large vessel occlusion for detecting occluded middle cerebral artery and internal carotid artery before acute mechanical thrombectomy.

OBJECTIVE: Acute mechanical thrombectomy (AMT) in patients with acute ischemic stroke from large vessel occlusion (LVO) is performed without directly identifying the occluded vessels. In this study, we evaluated whether 1.5 T magnetic resonance imaging (MRI) with 3D-fast imaging employing steady-state acquisition (FIESTA) could visualize the occluded intracranial middle cerebral artery (MCA) and internal carotid artery (ICA) before AMT. METHODS: This retrospective study included 21 consecutive patients who underwent time-of-flight magnetic resonance angiography (TOF MRA) and 3D-FIESTA MRI immediately before AMT. The patients also underwent TOF MRA after AMT and achieved TICI 2b or 3 by AMT at our hospital between February 2018 and April 2019. When LVO in the anterior circulation was detected by TOF MRA, 3D-FIESTA MRI was additionally performed. Then, the occluded intracranial MCA and ICA, including their branches, were constructed on the workstation with volume rendering. The obtained images were fused with the TOF MRA images to create combined 3D images. RESULTS: The length and top-to-bottom distance of the affected M1 segment (calculated by the ipsilateral-to-contralateral ratio) were 1.29 and 1.17, respectively, on 3D-FIESTA MRI before AMT and 1.34 and 1.24, respectively, on TOF MRA after AMT. We assessed the number of M2 segments branching from the affected M1/M2 junction and visualized the affected anterior temporal artery. The 3D-FIESTA MRI before AMT and TOF MRA after AMT were consistent in all patients, except for two who moved vigorously during imaging. CONCLUSIONS: Images acquired by 1.5T 3D-FIESTA MRI can visualize to predict the existing path of the occluded MCA and ICA before AMT in patients with LVO of the anterior circulation.

Early rebleeding of a foramen magnum dural arteriovenous fistula: A case report and review of the literature.

Foramen magnum dural arteriovenous fistula (FM-DAVF) is a subset of craniocervical junction arteriovenous fistulas. We report a rare case of FM-DAVF with early rebleeding and review the literature. A 50-year-old man experienced 3 episodes of intracranial bleeding from a vessel malformation in the acute stage. We identified an FM-DAVF, supplied by multiple feeding arteries (eg, left ascending pharyngeal artery) that drained into the straight sinus and left superior petrosal sinus. The draining vein had venous varices. We performed transarterial feeder embolization and surgical disconnection of the DAVF. Early rebleeding of FM-DAVF is rare. High-risk patients require risk assessment and appropriate treatment as soon as possible in the acute stage.

Prospective, Multicenter Clinical Study of Microvascular Decompression for Hemifacial Spasm.

BACKGROUND: Microvascular decompression (MVD) is the most effective procedure for hemifacial spasm (HFS). MVD results from nonspecialized or low-volume institutes are not always reliable. Most studies on MVD for HFS are retrospective and single centered; to the best of our knowledge, no prospective, multicenter studies exist. OBJECTIVE: To evaluate short- and long-term outcomes and complications in patients who underwent MVD for HFS in specialized Japanese institutions, in this multicenter, prospective, cohort study. METHODS: Included patients had undergone MVD for HFS in study centers between April 2012 and March 2015. Patients' postoperative grade of involuntary movements and complications were recorded postoperatively at 7 d (short-term) and at 1 (mid-term) and 3 (long-term) yr. RESULTS: A total of 486 patients (150 men, 336 women; mean age 53.9 yr with 181 patients over 60 yr) were enrolled during the study period. Neuromonitoring was used in 96.3% of the cases. The complete cure rate of symptom relief, mortality rate, and complication rate at short-term follow-up were 70.6%, 0%, and 15%, respectively. The long-term follow-up was completed by 463 patients (95.3%); the complete cure rate of symptom relief and complication rate were 87.1% and 3.0%, respectively. CONCLUSION: Our study revealed that under expert guidance and intraoperative neuromonitoring, the long-term curative effect rate of MVD for HFS is high, while complications are uncommon and usually transient. Our results indicate that MVD is an effective and safe treatment for patients with HFS, including elderly patients.

Clinical Results of Mechanical Thrombectomy in Nonagenarians with Acute Ischemic Stroke.

Objective: Multiple randomized trials have demonstrated the efficacy of mechanical thrombectomy (MT), but very elderly patients aged ≥90 years were excluded. It remains uncertain whether endovascular therapy is effective for nonagenarians. The objective of this study was to investigate the effectiveness and safety of MT in nonagenarians. Methods: Between January 2016 and March 2019, acute ischemic stroke patients aged ≥80 years who underwent MT at our hospital were retrospectively reviewed. Patients with a baseline pre-stroke modified Rankin Scale (mRS) score ≥3 were excluded from the analysis. They were divided into octogenarians (80-89 years old) and nonagenarians (90-99 years old). Results: Forty-five patients met the inclusion criteria, including 34 octogenarians and 11 nonagenarians. Nonagenarians were more likely to be female (47.0% vs 90.9%; p <0.05). There was a significantly lower rate of a pre-stroke mRS score of 0-1 among the nonagenarians (91.1% vs 63.6%; p <0.05). Revascularization was successful in 71.0% and 81.8% (p = 0.46) of octogenarians and nonagenarians, respectively. Functional independence (mRS ≤2) at discharge was observed in 26.4% vs 27.2% (p = 0.95) of octogenarians and nonagenarians, respectively. Conclusion: MT in nonagenarians can be considered safe without increasing hemorrhagic complications in comparison with that in octogenarians. One in four patients may have a good outcome and obtain effects equivalent to those in octogenarians if they have a good pre-stroke functional status.

Clinical Outcomes of Mechanical Thrombectomy for Acute Ischemic Stroke in Transfer Cases.

Objective: There are regional disparities in endovascular thrombectomy, and problems with emergency transport systems and hospital collaboration when transferring need to be addressed. In this study, the clinical outcomes of endovascular thrombectomy for transferred patients were analyzed. Methods: Acute ischemic stroke patients who underwent endovascular thrombectomy between January 2016 and March 2019 were enrolled. They were retrospectively reviewed and divided into the direct group and transfer group, and we compared treatment results and clinical outcomes between them. Results: In all, 122 patients met the inclusion criteria, comprising 93 patients in the direct group and 29 patients in the transfer group. The time from onset to door of our hospital was longer in the transfer group than in the direct group (73 minutes vs. 158 minutes, P = 0.80), but the time from arrival to reperfusion was significantly shorter in the transfer group (139 minutes vs. 106 minutes, P = 0.001). As the time from onset to reperfusion did not differ significantly between the two groups (220 minutes vs. 256 minutes, P = 0.60), there was no significant difference in good outcome at discharge (38.7 vs. 41.3%, P = 0.79). Conclusion: Clinical outcomes of transferred patients for endovascular thrombectomy may be equivalent to those of directly transported patients. Promoting close hospital cooperation may improve clinical outcomes and resolve regional disparities.

Parent Artery Occlusion for Treatment of a Traumatic Pericallosal Artery Aneurysm: Case Report and Review of the Literature.

BACKGROUND: Traumatic intracranial aneurysms are rare complications after head trauma. This report describes the case of a patient with a traumatic pericallosal aneurysm. CASE DESCRIPTION: A 73-year-old man developed headache and lower limb paresis, and emergency computed tomography scan revealed a hematoma in the corpus callosum. We performed coil embolization for a pericallosal aneurysm, but follow-up angiography showed recurrence of the aneurysm 6 days after the surgery. We diagnosed this as a traumatic aneurysm and subsequently performed parent artery occlusion without any complications. CONCLUSIONS: We performed parent artery occlusion for a traumatic aneurysm of the pericallosal artery without complications. Pericallosal aneurysms are rare, but we must consider them when encountering a delayed hematoma around the corpus callosum.

Mechanical Thrombectomy for Large Vessel Occlusion via the Transbrachial Approach: Case Series.

Mechanical thrombectomy has become a standard treatment for acute ischemic stroke with large vessel occlusion. In aged patients, it is difficult to guide the catheter via the transfemoral approach due to vessel tortuosity and aortic elongation. We report our preliminary clinical experience using the transbrachial approach. Among the 119 patients who underwent thrombectomy from April 2018 to December 2019, a total of 5 patients were treated via the transbrachial approach. Clinical outcomes were retrospectively analyzed. Successful reperfusion was achieved in 4 out of 5 cases. There was 1 death due to symptomatic intracranial hemorrhage. One patient had a good outcome at discharge. There were no access-site complications associated with any of these cases. Transbrachial access for mechanical thrombectomy is feasible and can provide an alternative to the transfemoral approach.

Brachial plexopathy due to massive swelling of the neck associated with craniotomy in the park bench position.

BACKGROUND: During prolonged neurosurgical procedures, anesthetized patients are at risk for position-related complications. We report a rare combination of neck swelling and brachial plexopathy as operative position-related complications. CASE DESCRIPTION: This 56-year-old woman was placed in the left park bench position for removal of a tentorial meningioma in the right posterior fossa. At 2 hours after the 10-hour procedure, her left neck began to swell with progression during the next 10 hours to involve the face on the same side and the face and neck on the opposite side. Computed tomography showed swelling of the muscles and deep soft tissue primarily on the left. No brain edema was observed. She was conservatively treated with orotracheal intubation, placed in the head-up position, and received anticoagulants. Her swelling subsided by the 20th postoperative day; however, she manifested weakness in the proximal muscles of the left upper extremity. Magnetic resonance imaging revealed swelling of the brachial plexus on the left; electrophysiologic studies were compatible with damage to the upper trunk of the brachial plexus. She was discharged 2 months after surgery with improved weakness. CONCLUSION: Possible pathologic mechanisms are kinking of the jugular vein due to extremely flexed neck position during surgery and associated delayed swelling of the neck and brachial plexus. The cerebral venous return may have been maintained by anastomosis between the internal jugular and the vertebral venous system. To prevent such complications, we must take great care of the anesthetized patients when placed in the forced neck position.

Continuous Fabrication of Monodisperse Ceria-Zirconia-Yttria Composite Oxide Nanoparticles Using a Novel High-Shear Agitation Reactor.

Monodisperse ceria-zirconia nanoparticles have attracted much attention as potential high-performance catalysts. Acidic aqueous solutions are generally used for peptizing aggregated precipitates during the fabrication of disperse nanoparticles. However, the peptization process requires multiple hours of aging, which significantly decreases the production efficiency. Hence, various researchers have attempted to eliminate this stage altogether by performing a coprecipitation process under ambient conditions using common salts as the starting materials. In this work, we report a continuous and direct technique for the fabrication of monodisperse composite oxide nanoparticles via coprecipitation inside a novel high-shear agitation reactor without aging. Using this method, monodisperse ceria-zirconia-yttria composite oxide nanoparticles with diameters of 3 nm were successfully synthesized.