Myung-Jin Kang

Pre-hospital notification reduced the door-to-needle time for iv t-PA in acute ischaemic stroke

Background and purpose:  Intrahospital delay is the most serious obstacle in thrombolysis in acute ischaemic stroke (AIS). We implemented the pre‐hospital notification system from the emergency medical information system in our metropolitan area to reduce intrahospital delay.

Initial phantom study comparing image quality in computed tomography using adaptive statistical iterative reconstruction and new adaptive statistical iterative reconstruction v.

Purpose The purpose of this study was to assess the image quality of a novel advanced iterative reconstruction (IR) method called as “adaptive statistical IR V” (ASIR-V) by comparing the image noise, contrast-to-noise ratio (CNR), and spatial resolution from those of filtered back projection (FBP) and adaptive statistical IR (ASIR) on computed tomography (CT) phantom image. Materials and Methods We performed CT scans at 5 different tube currents (50, 70, 100, 150, and 200 mA) using 3 types of CT phantoms. Scanned images were subsequently reconstructed in 7 different scan settings, such as FBP, and 3 levels of ASIR and ASIR-V (30%, 50%, and 70%). The image noise was measured in the first study using body phantom. The CNR was measured in the second study using contrast phantom and the spatial resolutions were measured in the third study using a high-resolution phantom. We compared the image noise, CNR, and spatial resolution among the 7 reconstructed image scan settings to determine whether noise reduction, high CNR, and high spatial resolution could be achieved at ASIR-V. Results At quantitative analysis of the first and second studies, it showed that the images reconstructed using ASIR-V had reduced image noise and improved CNR compared with those of FBP and ASIR (P < 0.001). At qualitative analysis of the third study, it also showed that the images reconstructed using ASIR-V had significantly improved spatial resolution than those of FBP and ASIR (P < 0.001). Conclusions Our phantom studies showed that ASIR-V provides a significant reduction in image noise and a significant improvement in CNR as well as spatial resolution. Therefore, this technique has the potential to reduce the radiation dose further without compromising image quality.

Reduced rCBV ratio in perfusion-weighted MR images predicts poor outcome after thrombolysis in acute ischemic stroke.

Recent research has suggested that a perfusion-weighted image (PWI) relative cerebral blood volume (rCBV) map after acute ischemic stroke (AIS) provides information about the collateral circulation in the ischemic region. In this study, we demonstrate the usefulness of the rCBV ratio in PWI in predicting poor outcome after using IV t-PA in AIS. We recruited 58 stroke patients who were treated with IV t-PA after diagnostic magnetic resonance imaging (MRI). Poor outcome was defined as a Modified Rankin Scale (mRS) score >2 measured 90 days after ischemic insult. In total, 21 patients (36.2%) demonstrated poor outcome (i.e. mRS score 3–6). Poor outcome after t-PA correlated with age (p = 0.03), serum glucose level (p = 0.01), NIHSS (p = 0.05), and the presence of T-occlusion (p = 0.05). Poor outcome also correlated with diffusion-weighted MR images of the lesion volume (p < 0.01), lower rCBV ratio on PWI (p < 0.01), and non-recanalization (p < 0.01). Among these, non-recanalization (p < 0.01), reduced rCBV ratio on PWI (p < 0.01), age (p = 0.04), and serum glucose level (p = 0.01) had an independent significance for predicting it. This suggests that the rCBV ratio on PWI may be used to determine prognosis after thrombolysis in AIS.

Pre-stroke glycemic control is associated with early neurologic deterioration in acute atrial fibrillation-related ischemic stroke

Background It has been suggested that AF-related ischemic stroke (IS) that is accompanied by atherosclerotic burden have poorer outcomes. The aim of this study was to investigate the importance of pre-stroke glycemic control (PSGC) on the early neurologic deterioration (END) of patients with acute AF-related IS. Methods We retrospectively recruited 121 patients with AF-related IS who also had Diabetes mellitus (DM). The HbA1C level was measured in all subjects. END was defined as an increase in the National Institute of Health Stroke Scale (NIHSS) score of 4 NIHSS points within 7 days of symptom onset compared to the initial NIHSS score. Results In this study, 20.7% (25 patients) were classified as having a poor PSGC status with a HbA1C level above 8.0%. In the univariate analysis, a poor PSGC status (p < 0.01), smoking (p = 0.01), severe neurologic deficits at admission (p = 0.01), and a larger size of ischemic lesions on DWI (p < 0.01) were associated with the occurrence of END. In the multivariate model, a poor PSGC status (p = 0.02) and larger size of ischemic lesions on MRI (p < 0.01) were independent predictors of END in acute AF-related IS. Conclusion The HbA1c level upon admission was independently associated with significant prediction of END in acute AF-related IS.

Relative CBV ratio on perfusion-weighted MRI indicates the probability of early recanalization after IV t-PA administration for acute ischemic stroke

Background We hypothesized that the relative cerebral blood volume (rCBV) ratio on perfusion-weighted imaging (PWI) using MRI might serve as a predictor of early recanalization (ER) after intravenous tissue plasminogen activator (IV t-PA) administration for acute ischemic stroke. Methods Patients with acute middle cerebral artery (MCA) ischemic stroke (IS) were enrolled in the study. They were evaluated by MRI, including PWI and diffusion-weighted imaging, before administration of IV t-PA and underwent digital subtraction angiography (DSA) of the brain within 2 h after t-PA administration. We compared the rCBV ratio on PWI between patients with and without ER on DSA and investigated the proportion of patients with an excellent outcome at 90 days after t-PA administration (modified Rankin Scale score 0–1) among those with and without ER. Results 85 patients with acute MCA IS were included; 16 patients (18.8%) experienced ER on DSA after IV t-PA administration. Patients with ER more frequently had an excellent outcome at 90 days than those without ER. The rCBV ratio on PWI was higher in the ER group (1.01±0.21, p<0.01) than in the non-ER group (0.82±0.18). After adjusting for the presence of atrial fibrillation and the serum glucose level, the rCBV ratio on PWI (OR 1.07; 95% CI 1.02 to 1.12; p<0.01) was a significant independent indicator of ER. Conclusions The results of this study suggest that the rCBV ratio on PWI might serve as a useful indicator of ER after IV t-PA administration.

Vasospastic Amaurosis Fugax Diagnosed by Cerebral Angiography

UNLABELLED We report a case of recurrent monocular blindness presumed to be caused by vasospasm, demonstrated by digital subtraction angiography. CASE REPORT A 65-year-old man presented with recurrent visual loss in the left eye for 2 years. He had histories of hypertension, cigarette smoking, and May-Thurner syndrome. The symptom occurred variably from twice a day to once a week and usually lasted for 5 minutes. Brain magnetic resonance imaging, magnetic resonance angiography, and ophthalmologic evaluation did not reveal any abnormality. Cerebral digital subtraction angiography was performed. On the left internal carotid angiogram, vasospasm occurred in the cervical portion of the left internal carotid artery and, subsequently, the blood flow to the left ophthalmic artery diminished. This phenomenon was reproducible and, in the absence of vasospasm, the ophthalmic artery was well visualized with no steno-occlusive lesion. Examination of the carotid duplex showed diffuse luminal narrowing and increased flow velocities in the left cervical internal carotid artery without atherosclerotic plaque. Treatment was started with nimodipine, which markedly reduced the attacks. CONCLUSION We assumed that vasomotor instability, which made the vessels vulnerable to spasm, may have caused a recurrent ocular symptom in our patient.

The Processing Time for Recanalization and Size of Ischemic Lesions on DWI is Related With Complete Reperfusion After Mechanical Thrombectomy

Recent studies demonstrated that modified thrombolysis in cerebral infarction (TICI) 3 reperfusion have better functional outcomes than modified TICI 2b after mechanical thrombectomy in acute ischemic stroke with large vessel occlusion. The purpose of this study was to determine significant factors to forecast the presence of complete reperfusion after mechanical thrombectomy based on multimodal magnetic resonance imaging (MRI). We investigated 96 consecutive patients with acute large intracranial artery occlusion of anterior circulation who based on multimodal MRI. Also, we compared clinical and radiologic parameters between patients with modified TICI 3 and those with modified TICI 0-2b. Among 96 eligible subjects received mechanical thrombectomy, 39 patients (40.6%) showed complete reperfusion and 57 partial or nonreperfusion (mTICI 2b-26, mTICI 2a-9, mTICI 1-8, and mTICI 0-14) after mechanical thrombectomy. Patients with mTICI 3 had significantly smaller initial Diffusion weighted images (DWI) lesion volume (P < .01) and much shorter time interval from onset to reperfusion (P < .01) than those patients with mTICI (0-2b). In multivariate analysis, smaller initial DWI volume (odds ratio [OR], 1.78; 95% confidence interval [CI], 1.23-2.57; P < .01) and faster reperfusion time (OR, 1.07; 95% CI 1.01-1.14; P = .015) had an independence significance for complete reperfusion after mechanical thrombectomy. In this study, the ischemic lesion volume on DWI and faster processing time are critical factor to predict the state of complete reperfusion after mechanical thrombectomy.

Factors associated with early dramatic recovery following successful recanalization of occluded artery by endovascular treatment in anterior circulation stroke

Endovascular treatment (EVT) significantly increases the recanalization rate and improves functional outcomes in acute ischemic stroke. However, despite successful recanalization by EVT, some stroke patients demonstrate no early dramatic recovery (EDR). We assessed factors associated with EDR following recanalization by EVT. We included subjects with anterior circulation stroke treated with EVT who met the following criteria: Thrombolysis in Cerebral Ischemia scores (TICI) 2b-3 after EVT, lesion volume <70mL as seen on the pre-treatment diffusion-weighted imaging (DWI) scan and a baseline NIHSS score ≥6. EDR was defined as a ≥8-point reduction in the NIHSS score, or NIHSS score of 0 or 1 measured 24h following treatment. Multivariate regression analyses were performed to identify the predictors associated with EDR. Of the 102 patients (mean age, 64.3years; median National Institutes of Health Stroke Scale score, 14), EDR was achieved in 39 patients (38.2%). The median DWI lesion volume was 12mL (interquartile range, 5-25mL). Median onset-to-recanalization time in these patients was 320min (interquartile range, 270-415min). Logistic regression analysis identified a higher initial NIHSS score (OR 1.17, 95% CI 1.03-1.33, P=0.016) and shorter time from onset to recanalization (OR 0.99, 95% CI 0.986-0.997, P=0.003), to be independently associated with EDR. In the setting of pretreatment DWI lesion volume <70mL, a higher initial NIHSS score and faster time from onset to recanalization may be important predictors of EDR following successful EVT.