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"Tokunaga, So"
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Efficacy of combined use of a stent retriever and aspiration catheter in mechanical thrombectomy for acute ischemic stroke
by
Yamaguchi, Shinya
,
Uwatoko, Takeshi
,
Mizoguchi, Masahiro
in
Angioplasty
,
Blood clots
,
Carotid arteries
2022
BackgroundThe efficacy of combined stent retriever (SR) and aspiration catheter (AC; combined technique: CBT) use for acute ischemic stroke (AIS) is unclear. We investigated the safety and efficacy of single-unit CBT (SCBT)—retrieving the thrombus as a single unit with SR and AC into the guide catheter—compared with single use of either SR or contact aspiration (CA).MethodsWe analysed 763 consecutive patients who underwent mechanical thrombectomy for AIS between January 2013 and January 2020, at six comprehensive stroke centers. Patients were divided into SCBT and single device (SR/CA) groups. The successful recanalization with first pass (SRFP) and other procedural outcomes were compared between groups.ResultsOverall, 240 SCBT and 301 SR/CA (SR 128, CA 173) patients were analyzed. SRFP (modified Thrombolysis In Cerebral Infarction (mTICI) ≥2c, 43.3% vs 27.9%, p<0.001; mTICI 3, 35.8% vs 25.5%, p=0.009) and final mTICI ≥2b recanalization (89.1% vs 82.0%, p=0.020) rates were significantly higher, puncture-to-reperfusion time was shorter (median (IQR) 43 (31.5–69) vs 55 (38–82.2) min, p<0.001), and the number of passes were fewer (mean±SD 1.72±0.92 vs 1.99±1.01, p<0.001) in the SCBT group. Procedural complications were similar between the groups. In subgroup analysis, SCBT was more effective in women, cardioembolic stroke patients, and internal carotid artery and M2 occlusions.ConclusionsSCBT increases the SRFP rate and shortens the puncture-to-reperfusion time without increasing procedural complications.
Journal Article
Interaction between the stent strut and thrombus characterized by contrast-enhanced high-resolution cone beam CT during deployment of the Solitaire stent retriever
2017
BackgroundThe mechanism by which a stent retriever removes intraluminal thrombus from an occluded vessel in humans has not previously been studied. This study performed contrast-enhanced high-resolution cone beam CT (CE-HRCBCT) during deployment of the stent retriever to observe the interaction between the strut and intraluminal thrombus intraoperatively. We also discuss the mechanism by which the thrombus is retrieved.MethodsIn 11 patients, mechanical thrombectomy was performed with a Solitaire stent retriever. The presence or absence of flow restoration (FR) was evaluated immediately and at least 5 min after deployment. Stent retriever findings on CE-HRCBCT were divided into two groups: (1) complete expansion; and (2) incomplete expansion.ResultsFR was observed in all 11 cases (100%) immediately after deployment of the Solitaire stent retriever. Complete expansion was observed in only one case and incomplete expansion was observed in 10 cases. The thrombus was observed mainly near to or outside the strut of the stent retriever by CE-HRCBCT. Loss of FR was seen in only one of the 11 cases. Regardless of this, successful recanalization was achieved with only the stent retriever in nine cases.ConclusionsCE-HRCBCT showed that the Solitaire stent retriever rarely expanded fully and the thrombus was mainly near to or outside the strut. It may not be necessary to wait a long time to allow the stent to expand fully into the thrombus because the main capture mechanism seems to be engagement of the clot between the crossings of the struts of the Solitaire.
Journal Article
Risk factors for and outcomes of intraprocedural rupture during endovascular treatment of unruptured intracranial aneurysms
by
Suzuki, Keita
,
Imamura, Hirotoshi
,
Adachi, Hidemitsu
in
Adult
,
Aged
,
Aneurysm, Ruptured - diagnostic imaging
2018
Background and purposeThe risk factors for intraprocedural rupture (IPR) of unruptured intracranial aneurysms (UIAs) and the outcomes of IPR itself are unclear. This study was performed to identify the independent risk factors for and outcomes of IPR.Materials and methodsWe retrospectively evaluated the medical records and radiologic data of 1375 patients (1406 UIAs) who underwent coil embolization from January 2001 to October 2016.ResultsIPR occurred in 20 aneurysms of 20 patients (1.4%). Univariate analyses showed that the rate of IPR was significantly higher in the treatment of aneurysms with a small dome size, aneurysms in the anterior communicating artery (AcomA) (6.6%), and patients with a medical history of dyslipidemia. Multivariate analyses showed that a small dome size and aneurysms in the AcomA were independently associated with IPR (p=0.0096 and p=0.0001, respectively). IPR induced by a microcatheter was associated with a higher risk of severe subarachnoid hemorrhage than other causes of IPR (57% vs 0%, respectively). Thromboembolic complications occurred in seven (35%) patients with IPR. Six (30%) patients required external ventricular drainage placement after developing symptoms of acute hydrocephalus. The overall morbidity and mortality rates from IPR were 0.22% and 0.15%, respectively.ConclusionsAneurysms in the AcomA and with a small dome size are likely to be risk factors for IPR. IPR induced by microcatheters can result in poor outcomes. The rate of IPR-associated thromboembolic complications is high, and IPR itself is associated with acute hydrocephalus. If managed appropriately, however, most patients with IPR can survive without neurological deterioration.
Journal Article
Endovascular Therapy for Acute Stroke with a Large Ischemic Region
by
Yazawa, Yukako
,
Matsumoto, Yasushi
,
Beppu, Mikiya
in
Body weight
,
Brain Ischemia - diagnostic imaging
,
Brain Ischemia - drug therapy
2022
Endovascular therapy for stroke is generally avoided if the cerebral infarction is large. In a trial conducted in Japan, the percentage of patients who had a good functional outcome at 90 days was higher with endovascular therapy than with medical care, but there were more cerebral hemorrhages with endovascular therapy.
Journal Article
First-in-man experience of the Versi Retriever in acute ischemic stroke
2019
ObjectiveTo describe our initial experience with the Versi Retriever for mechanical thrombectomy in patients with acute ischemic stroke.MethodsThis study is a single-center, single-arm, first-in-man registry under institutional review board control to evaluate the efficacy and safety of the new stent retriever, the Versi Retriever. Patients with acute ischemic stroke were consecutively enrolled between September and November 2017. The clinical and procedural data were retrospectively analyzed. The angiographic result after the procedure was self-graded based on the Thrombolysis in Cerebral Infarction (TICI) scale by each operator.ResultsEleven patients with a mean age of 69.4 years were treated with the Versi Retriever. Median National Institutes of Health Stroke Scale score on admission was 16 (IQR 10–34). The occluded vessel was located in the anterior circulation in 81.8%. Revascularization rates of TICI 2b–3 and TICI 3 at final angiogram were achieved in 100% and 63.6%, respectively. A favorable functional outcome (modified Rankin Scale 0–2) at 90 days was obtained in 72.7%. No symptomatic intracranial hemorrhage occurred and no procedure-related complication was observed.ConclusionsOur initial experience suggests that the Versi Retriever is a safe and effective stent retriever for mechanical thrombectomy in patients with acute ischemic stroke.Clinical trial registrationNCT03366818
Journal Article
Correction: Study protocol of the ASTOP trial: A multicenter, randomized, double-blind, placebo-controlled trial of presurgical aspirin administration for the prevention of thromboembolic complications of coil embolization for ruptured aneurysms
2025
[This corrects the article DOI: 10.1371/journal.pone.0310906.].
Journal Article
Study protocol of the ASTOP trial: A multicenter, randomized, double-blind, placebo-controlled trial of presurgical aspirin administration for the prevention of thromboembolic complications of coil embolization for ruptured aneurysms
2024
Thromboembolism is a serious complication of endovascular treatment for ruptured cerebral aneurysms. The administration of antiplatelet agents before endovascular treatment for ruptured cerebral aneurysms may reduce the risk of thromboembolic complications.
This study aimed to assess the safety and efficacy of preoperative aspirin administration in endovascular treatment for ruptured cerebral aneurysms.
Assuming a 15% incidence rate of both intraoperative thromboembolic morbidity and symptomatic ischemic lesions on magnetic resonance imaging diffusion-weighted imaging scans assessed by an Independent Review Committee, a sample size of 484 will be required to detect a 10% improvement with aspirin administration with 90% power using the Pearson's chi-square test at a two-sided significance level of 2.5% for each primary outcome, after accounting for a 5% dropout rate.
ASTOP is a multicenter, randomized, double-blind, placebo-controlled clinical trial. A total of 484 patients with ruptured cerebral aneurysms receiving coil embolization within 72 h of onset will be randomly assigned 1:1 to receive 200 mg of aspirin or placebo before the procedure.
The primary outcomes will be the incidence rates of intraoperative thromboembolic complications and symptomatic ischemic lesions on magnetic resonance imaging diffusion-weighted imaging scans evaluated by the Independent Review Committee. The secondary outcomes will be the incidence rate of cerebral ischemic events and all bleeding events within 14 days of enrollment and functional outcomes defined by the modified Rankin Scale score at 90 days.
This trial will provide valuable data on the role of antiplatelet agents during endovascular treatment for ruptured cerebral aneurysms.
Registration: Japan Registry of Clinical Trials, Identifier: jRCTs031210421.
Journal Article
Multicenter clinical trial evaluating the safety and efficacy of mechanical thrombectomy using the Versi Retriever
by
Ohara, Nobuyuki
,
Fujinaka, Toshiyuki
,
Kuwayama, Naoya
in
Aged
,
Aged, 80 and over
,
Anticoagulants
2025
BackgroundThis study aimed to elucidate the safety and efficacy of mechanical thrombectomy using the Versi Retriever in patients with acute ischemic stroke (AIS).MethodsThis was a prospective, multicenter, single-arm study conducted at 10 institutes in Japan from December 2018 to March 2021 on mechanical thrombectomy using the Versi Retriever in patients with AIS. The primary efficacy outcome was the modified Rankin scale (mRS) 0–2 at 90 days after the procedure. The primary safety outcome was mortality within 90 days after the procedure.ResultsFifty-eight patients with a mean age of 72.7 years were enrolled in the study. The primary efficacy outcome of mRS 0–2 at 90 days was 62.0% (95% CI 47.2–75.3%) in patients within 8 hours of stroke onset. The rate of immediate reperfusion of Thrombolysis in Cerebral Infarction (TICI) grade 2b-3 using the Versi Retriever in three passes was 78.0% (64.0–88.5%). The rate of final reperfusion of TICI 2b-3 was 100% (92.9–100%). The primary safety outcome of mortality within 90 days was 8.0% (2.2–19.2%) in patients within 8 hours of AIS onset. The incidence of intracranial hemorrhage within 24 hours was 12.0% (4.5–24.3%) for symptomatic cases and 32.0% (19.5–46.7%) for asymptomatic cases.ConclusionThe Versi Retriever proved to be a safe and effective option for mechanical thrombectomy in patients with AIS.
Journal Article
Compositional differences between meteorites and near-Earth asteroids
2008
Hazardous asteroids: where they are coming from
New spectral measurements of near-Earth asteroids reveal, as might be expected, overall compositions similar to the most commonly falling meteorites, the ordinary chondrites. But the compositional distribution is un-expected: about two-thirds of near-Earth asteroids, including those most likely to hit us, match the class of meteorites known as LL chondrites, which comprise only about 8% of all meteorite falls. This may reflect an origin at the asteroid belt's inner edge, where the family of asteroids produced by the break-up of the Flora parent body predominates. A possible explanation might lie in the involvement of size-dependent processes in the transport of material from the main asteroid belt to the vicinity of Earth's orbit.
The compositions of the asteroids most likely to hit the Earth are expected to reflect that of the most common meteorites. Vernazza
et al
. report that most potentially hazardous and near-Earth asteroids have spectral properties similar to LL chondrites, a class of meteorites that is relatively rare.
Understanding the nature and origin of the asteroid population in Earth’s vicinity (near-Earth asteroids, and its subset of potentially hazardous asteroids) is a matter of both scientific interest and practical importance
1
. It is generally expected that the compositions of the asteroids that are most likely to hit Earth should reflect those of the most common meteorites. Here we report that most near-Earth asteroids (including the potentially hazardous subset) have spectral properties quantitatively similar to the class of meteorites known as LL chondrites. The prominent Flora family in the inner part of the asteroid belt shares the same spectral properties, suggesting that it is a dominant source of near-Earth asteroids. The observed similarity of near-Earth asteroids to LL chondrites is, however, surprising, as this meteorite class is relatively rare (∼8 per cent of all meteorite falls). One possible explanation is the role of a size-dependent process, such as the Yarkovsky effect, in transporting material from the main belt.
Journal Article
Highly inclined thin illumination enables clear single-molecule imaging in cells
by
Imamoto, Naoko
,
Sakata-Sogawa, Kumiko
,
Tokunaga, Makio
in
Bioinformatics
,
Biological Microscopy
,
Biological Techniques
2008
We describe a simple illumination method of fluorescence microscopy for molecular imaging. Illumination by a highly inclined and thin beam increases image intensity and decreases background intensity, yielding a signal/background ratio about eightfold greater than that of epi-illumination. A high ratio yielded clear single-molecule images and three-dimensional images using cultured mammalian cells, enabling one to visualize and quantify molecular dynamics, interactions and kinetics in cells for molecular systems biology.
Journal Article