• Journal of Korean Neurosurgical Society
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• v.67 no.1
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• pp.31-41
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• 2024

Objective : Collateral circulation is associated with the differential treatment effect of endovascular thrombectomy (EVT) in acute ischemic stroke. We aimed to verify the ability of the collateral map to predict futile EVT in patients with acute anterior circulation ischemic stroke. Methods : This secondary analysis of a prospective observational study included data from participants underwent EVT for acute ischemic stroke due to occlusion of the internal carotid artery and/or the middle cerebral artery within 8 hours of symptom onset. Multiple logistic regression analyses were conducted to identify independent predictors of futile recanalization (modified Rankin scale score at 90 days of 4-6 despite of successful reperfusion). Results : In a total of 214 participants, older age (odds ratio [OR], 2.40; 95% confidence interval [CI], 1.56 to 3.67; p<0.001), higher baseline National Institutes of Health Stroke Scale (NIHSS) scores (OR, 1.12; 95% CI, 1.04 to 1.21; p=0.004), very poor collateral perfusion grade (OR, 35.09; 95% CI, 3.50 to 351.33; p=0.002), longer door-to-puncture time (OR, 1.08; 95% CI, 1.02 to 1.14; p=0.009), and failed reperfusion (OR, 3.73; 95% CI, 1.30 to 10.76; p=0.015) were associated with unfavorable functional outcomes. In 184 participants who achieved successful reperfusion, older age (OR, 2.30; 95% CI, 1.44 to 3.67; p<0.001), higher baseline NIHSS scores (OR, 1.12; 95% CI, 1.03 to 1.22; p=0.006), very poor collateral perfusion grade (OR, 4.96; 95% CI, 1.42 to 17.37; p=0.012), and longer door-to-reperfusion time (OR, 1.09; 95% CI, 1.03 to 1.15; p=0.003) were associated with unfavorable functional outcomes. Conclusion : The assessment of collateral perfusion status using the collateral map can predict futile EVT, which may help select ineligible patients for EVT, thereby potentially reducing the rate of futile EVT.

• Journal of Korean Neurosurgical Society
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• v.56 no.6
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• pp.463-468
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• 2014

Objective : Unexpected Solitaire stent detachment can occur during mechanical Solitaire thrombectomy. The purpose of this study was to retrospectively evaluate the influencing factors causing unexpected Solitaire stent detachment and the clinical outcomes. Methods : Between October 2011 to December 2013, 232 cases of mechanical Solitaire thrombectomy for acute ischemic stroke were performed in 3 stroke centers. During this period, we encountered unexpected Solitaire stent detachments during mechanical Solitaire thrombectomies in 9 cases. Results : Solitaire stents unexpectedly detached in 9 cases (3.9%) during the retrieval of Solitaire stents. The median patient age was 76 years. The occlusion sites of the unexpected stent detachment were the proximal middle cerebral artery (MCA) in 7 cases and the internal carotid artery in 2 cases. The sizes of the stents that unexpectedly detached were $6{\times}30$ mm in 7 cases, $5{\times}30$ mm in 1 case, and $4{\times}20$ mm in 1 case. Four patients had unexpected detachment at the first retrieval, 1 patient at the second, 3 patients at the third, and 1 patient at the fifth. In all of the cases of unexpected detachment at the first retrieval, the stent deployment site was the proximal MCA. After detachment, a proximal marker of the Solitaire stent was observed in 3 patients. However, no marker was visible in the remaining 6 patients. Conclusion : Unexpected Solitaire stent detachment should be considered in the first instance of stent retrieval for a relatively large-diameter stent, especially in elderly patients with MCA occlusions.

• Journal of Korean Neurosurgical Society
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• v.60 no.6
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• pp.635-643
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• 2017

Objective : Acute basilar artery occlusion (BAO) is associated with severe neurological dysfunction and high mortality rates. The benefits of mechanical thrombectomy in BAO have not been explored in recent clinical trials. Therefore, we analyzed outcomes of stent retriever mechanical thrombectomy for BAO, and compared with anterior circulation occlusions (ACO). Methods : In total, 161 consecutive patients (24 BAO, 137 ACO) who underwent mechanical thrombectomy with the stent retriever between January 2013 and August 2016 enrolled in our study. All patients underwent clinical assessment with the National Institutes of Health Stroke Scale (NIHSS) and modified Rankin scale (mRS). Radiological results were used to evaluate thrombolysis in cerebral infarction (TICI) scores and successful recanalization was defined by TICI 2b or 3. Results : Mean NIHSS scores at 24 hours and 30 days were significantly higher in the BAO group than the ACO group (p=0.021, p=0.001). mRS at 90 days was significantly higher in the BAO group (4.2) compared with the ACO group (3.0) (p=0.003). The BAO group (2.0) performed fewer stent retriever passages than the ACO group (2.7) (p=0.049). There were no significant differences between the two groups in terms of complications, but the BAO patients experienced a higher mortality (16.6%) rate than ACO patients (5.8%) (p=0.001). In subgroup analysis of BAO, patients with short procedure times achieved successful recanalization (p=0.001) and successfully recanalized patients exhibited more favorable mRS at 90 days (p=0.027). Conclusion : In our study, mechanical thrombectomy of BAO patients showed worse clinical outcome and higher mortality rate than ACO patients. However, mechanical thrombectomy with a stent retriever in BAO is an effective treatment, because successfully recanalized patients showed good clinical outcome in BAO patients.

• Investigative Magnetic Resonance Imaging
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• v.7 no.2
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• pp.116-123
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• 2003

Purpose : The present study was undertaken to evaluate the usefulness of cerebral diffusion (DWI) and perfusion MR imaging (PWI) in rabbit models with hyperacute cerebral ischemic infarction. Materials and Methods : Experimental cerebral infarction were induced by direct injection of mixture of Histoacryl glue, lipiodol, and tungsten powder into the internal cerebral artery of 6 New-Zealand white rabbits, and they underwent conventional T1 and T2 weighted MR imaging, DWI, and PWI within 1 hour after the occlusion of internal cerebral artery. The PWI scan for each rabbit was obtained at the level of lateral ventricle and 1cm cranial to the basal ganglia. By postprocessing using special imaging software, perfusion images including cerebral blood volume (CBV), cerebral blood flow (CBF), and mean transit time (MTT) maps were obtained. The detection of infarcted lesion were evaluated on both perfusion maps and DWI. MTT difference time were measured in the perfusion defect lesion and symmetric contralateral normal cerebral hemisphere. Results : In all rabbits, there was no abnormal signal intensity on T2WI. But on DWI, abnormal high signal intensity, suggesting cerebral infarction, were detected in all rabbits. PWI (rCBV, CBF and MTT map) also showed perfusion defect in all rabbits. In four rabbits, the calculated square of perfusion defect in MTT map is larger than that of CBF map and in two rabbits, the calculated size of perfusion defect in MTT map and CBF map is same. Any rabbits do not show larger perfusion defect on CBF map than MTT map. In comparison between CBF map and DWI, 3 rabbits show larger square of lesion on CBF map than on DWI. The others shows same square of lesion on both technique. The size of lesion shown in 6 MTT map were larger than DWI. In three cases, the size of lesion shown in CBF map is equal to DWI. But these were smaller than MTT map. The calculated square of lesion in CBF map, equal to that of DWI and smaller than MTT map was three. And in one case, the calculated square of perfusion defect in MTT map was largest, and that of DWI was smallest. Conclusion : DWI and PWI may be useful in diagnosing hyperacute cerebral ischemic infarction and in e-valuating the cerebral hemodynamics in the rabbits.

• Journal of Korean Neurosurgical Society
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• v.65 no.5
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• pp.665-679
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• 2022

Objective : Patients with mild ischemic stroke experience various sequela and residual symptoms, such as anxious behavior and deficits in movement. Few approaches have been proved to be effective and safe therapeutic approaches for patients with mild ischemic stroke by acute stroke. Sildenafil (SIL), a phosphodiesterase-5 inhibitor (PDE5i), is a known remedy for neurodegenerative disorders and vascular dementia through its angiogenesis and neurogenesis effects. In this study, we investigated the efficacy of PDE5i in the emotional and behavioral abnormalities in rats with mild ischemic stroke. Methods : We divided the rats into four groups as follows (n=20, respectively) : group 1, naïve; group 2, middle cerebral artery occlusion (MCAo30); group 3, MCAo30+SIL-pre; and group 4, MCAo30+SIL-post. In the case of drug administration groups, single dose of PDE5i (sildenafil citrate, 20 mg/kg) was given at 30-minute before and after reperfusion of MCAo in rats. After surgery, we investigated and confirmed the therapeutic effect of sildenafil on histology, immunofluorescence, behavioral assays and neural oscillations. Results : Sildenafil alleviated a neuronal loss and reduced the infarction volume. And results of behavior task and immunofluorescence shown possibility that anti-inflammation process and improve motor deficits sildenafil treatment after mild ischemic stroke. Furthermore, sildenafil treatment attenuated the alteration of theta-frequency rhythm in the CA1 region of the hippocampus, a known neural oscillatory marker for anxiety disorder in rodents, induced by mild ischemic stroke. Conclusion : PDE5i as effective therapeutic agents for anxiety and movement disorders and provide robust preclinical evidence to support the development and use of PDE5i for the treatment of mild ischemic stroke residual disorders.

• Investigative Magnetic Resonance Imaging
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• v.21 no.2
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• pp.65-70
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• 2017

Purpose: To optimize the saturation time and maximizing the pH-weighted difference between the normal and ischemic brain regions, on 3-tesla amide proton transfer (APT) imaging using an in vivo rat model. Materials and Methods: Three male Wistar rats underwent middle cerebral artery occlusion, and were examined in a 3-tesla magnetic resonance imaging (MRI) scanner. APT imaging acquisition was performed with 3-dimensional turbo spin-echo imaging, using a 32-channel head coil and 2-channel parallel radiofrequency transmission. An off-resonance radiofrequency pulse was applied with a Sinc-Gauss pulse at a $B_{1,rms}$ amplitude of $1.2{\mu}T$ using a 2-channel parallel transmission. Saturation times of 3, 4, or 5 s were tested. The APT effect was quantified using the magnetization-transfer-ratio asymmetry at 3.5 ppm with respect to the water resonance (APT-weighted signal), and compared with the normal and ischemic regions. The result was then applied to an acute stroke patient to evaluate feasibility. Results: Visual detection of ischemic regions was achieved with the 3-, 4-, and 5-s protocols. Among the different saturation times at $1.2{\mu}T$ power, 4 s showed the maximum difference between the ischemic and normal regions (-0.95%, P = 0.029). The APTw signal difference for 3 and 5 s was -0.9% and -0.7%, respectively. The 4-s saturation time protocol also successfully depicted the pH-weighted differences in an acute stroke patient. Conclusion: For 3-tesla turbo spin-echo APT imaging, the maximal pH-weighted difference achieved when using the $1.2{\mu}T$ power, was with the 4 s saturation time. This protocol will be helpful to depict pH-weighted difference in stroke patients in clinical settings.

• Journal of Korean Neurosurgical Society
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• v.64 no.5
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• pp.732-739
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• 2021

Objective : Early successful reperfusion is associated with favorable outcomes in acute ischemic stroke (AIS). The purpose of this study was to achieve successful recanalization by a combined mechanical thrombectomy technique, the Aspiration-Retriever Technique for Stroke (ARTS), which is composed of a flexible large lumen distal access catheter and a retrievable stent as the first-line strategy of mechanical thrombectomy. Methods : We retrospectively reviewed 62 patients with AIS who underwent mechanical thrombectomy from 2018 to 2019 at our institute by a senior neurointerventionalist. Among them, patients who were treated using the ARTS technique with the soft torqueable catheter optimized for intracranial access (SOFIA^®; MicroVention-Terumo, Tustin, CA, USA) as the first-line treatment were included. Patients who had tandem occlusions or underlying intracranial artery stenosis were excluded. The angiographic and clinical outcomes were evaluated. The angiographic outcome was analyzed by the rate of successful recanalization, defined as a Thrombolysis in Cerebral Infarction score of 2b or 3 at the end of all procedures and the rate of successfully achieving the first pass effect (FPE), defined as complete recanalization with a single pass of the device. The clinical outcomes included the National Institutes of Health Stroke Scale (NIHSS) score, modified Rankin Scale (mRS), and mortality. Results : A total of 27 patients (mean age, 59.3 years) fulfilled the inclusion criteria. The successful recanalization rate was 96% (n=26) while the FPE rate was 41% (n=11). The mean post-procedural NIHSS change was -3.0. Thirteen patients (48%) showed good clinical outcomes after thrombectomy with the ARTS technique (mRS at 90 days ≤2). Postoperative complications occurred in seven of 25 patients : hemorrhagic transformation in six patients (22%) and distal embolization in one patient (4%). Mortality was 15% (n=4). Conclusion : Although the clinical outcomes using the ARTS technique with a flexible large lumen distal access catheter performed as the frontline thrombectomy in patients with AIS were not significantly superior than those of other studies, this study showed a high rate of successful endovascular recanalization which was comparable to that of other studies. Therefore, ARTS using the SOFIA^® catheter can be considered as the first choice of treatment for AIS due to large vessel occlusion.