[Signifiance of brush sign on susceptibility-weighted imaging predicts hemorrhagic transformation after intravenous thrombolysis in patients with acute ischemic stroke].

OBJECTIVE: To assess brush sign (BS) on susceptibility-weighted imaging (SWI) in prediction of hemorrhagic transformation (HT) in patients with acute ischemic stroke (AIS) after intravenous thrombolysis(IVT). METHODS: Patients with acute cerebral ischemic stroke, who had major cerebral artery occlusion (internal carotid artery, middle cerebral artery M1 and M2), treated with intravenous recombinant tissue plasminogen activator (rt-PA) from August 2009 to October 2014 in the Second Affiliated Hospital, Zhejiang University School of Medicine, were enrolled in the study. All patients underwent SWI scanning. The asymmetry index (AI) was defined as the difference of intensity between ischemic and normal hemispheres on the SWI phase map; according to AI values patients were divided into 3 groups: BS=0(n=9), BS=1 (n=39) and BS=2 (n=18). The relationships between BS and HT and the clinical outcome among the 3 groups were analyzed. RESULTS: Sixty-six patients aged 68 ± 13 years were included in the study, including 44 males (67%) and 22 females (33%), and 44 (67%) with acute ischemic stroke. The mean pre-treatment National Institutes of Health Stroke Scale (NIHSS) score was 13 (6-17), and the onset to needle time was (252 ± 88) min. Twenty-six (39.4%) patients had HT, including 18 cases (27.3%) with HI and 8 cases (12.1%) with PH; BS was observed more frequently in HT group than non-HT group. Binary logistic regression analysis showed that BS was independently associated with HT of patients with acute ischemic stroke following IVT (OR=2.589, 95% CI: 1.080-6.210, P=0.033). In those without reperfusion after IVT, patients with higher BS grade had higher HT rate (P=0.023). CONCLUSION: Brush sign on SWI can be used for predicting hemorrhagic transformation after intravenous thrombolysis in patients with acute ischemic stroke.

[Cerebral lesions of DWI hyperintensity in patients with subacute stroke assessed by intravoxel incoherent motion technique].

OBJECTIVE: To investigate the cerebral lesions of diffusion weighted imaging (DWI) hyperintensity in patients with subacute stroke with intravoxel incoherent motion (IVIM) technique. METHODS: The clinical data of 20 patients with ischemic stroke (3 to 7 d after onset) who underwent DWI and IVIM scanning between June 2014 and July 2015, were retrospectively analyzed. The parameters from IVIM including slow diffusion coefficient (D), fast diffusion coefficient (D(*)) and perfusion fraction (f) were processed. DWI hyperintensity was segmented by its signal intensity greater than the mean+2 standard deviations of the value in the homologous contralateral region. Then, DWI hyperintensity was classified into two regions of interest (ROIs): infarction core and peri-core with the ADC threshold of 0.55 × 10⁻³ mm²/s. The mirrored ROIs of infarction core and peri-core were also obtained. Then, we measured the values of ADC and D, D(*) and f in these ROIs. The ratios of ADC (rADC), D (rD), D(*) (rD(*)) and f (rf) were also calculated (e.g., rADC=ADCinfarction core/ADCmirrored region). RESULTS: Compared with mirrored region, ADC, D and f in the infarction core region decreased by 45% (P<0.001), 42% (P<0.001) and 32% (P<0.001), respectively; while ADC, D and f in the peri-core region decreased by 22% (P<0.001), 32% (P<0.001) and 8% (P=0.009), respectively. The values of rADC, rD, rD(*) and rf in the infarction core region were significantly lower than those in the peri-core region (all P<0.001). Pearson analysis showed that rADC was positively correlated with rf in the peri-core region (r=0.467, P=0.038). CONCLUSION: During subacute stage of stroke, compared to the infarction core region within DWI hyperintensity, D and f increase in the peri-core region of DWI hyperintensity, reflecting the increased water diffusion in microstructure and perfusion volume in microvasculature. This result shows that the potential reason for the heterogeneous ADC signal is associated with the disappearance of cellular edema and microvascular compensatory with increased blood volume.

[Older age is not related to hemorrhagic transformation and favorable outcomes in patients with wake-up ischemic stroke undergoing intravenous thrombolytic therapy].

OBJECTIVE: To investigate factors related to hemorrhagic transformation and favorable outcomes in wake-up ischemic stroke (WUIS) patients undergoing intravenous thrombolytic therapy. METHODS: Clinical data of 600 patients undergoing multimodal image-guided intravenous recombinant tissue plasminogen activator (rt-PA) therapy in Department of Neurology, the Second Affiliated Hospital, Zhejiang University School of Medicine center from May 2009 to May 2015 were retrospectively analyzed. Among 600 patients, 68 were diagnosed as WUIS including 17 cases aged 80 or older. Hemorrhagic transformation within the first 24 h after thrombolysis was assessed according to ECASS II criteria. Favorable outcome was defined as three-month modified Rankin Scale (mRS) 0-3. Univariate and binary logistic regression were used to analyze the risk factors of hemorrhagic transformation and poor clinical outcomes in WUIS patients. RESULTS: Univariate analysis showed that WUIS patients aged ≥ 80 years had a lower rate in males (41.2% vs 76.5%, P=0.007), smokers (11.8% vs 43.1%, P=0.019) and favorable outcome (52.9% vs 78.4%, P=0.043); and a higher rate of cardiac embolism (64.7% vs 35.3%, P=0.034) compared with those aged <80 years. Binary logistic regression showed that age was not an independent risk factor for favorable outcome (OR=0.524, 95% CI:0.141-1.953, P=0.336) or hemorrhagic transformation (OR=1.039, 95% CI: 0.972-1.111, P=0.262). CONCLUSION: Older age is not related to the favorable outcome or hemorrhagic transformation in WUIS patients undergoing multimodal image-guided intravenous thrombolytic therapy.

[Dynamic CT angiography in evaluation of collateral flow and outcome of acute ischemic stroke patients after intravenous thrombolysis].

OBJECTIVE: To evaluate the collateral flow of patients with acute ischemic stroke by dynamic CT angiography (CTA) and to analyze the relationship between collateral flow and outcome after intravenous thrombolysis. METHODS: We retrospectively analyzed CT perfusion (CTP) imaging of 22 acute ischemic stroke patients with middle cerebral artery (MCA) or internal carotid artery (ICA) occlusion undergoing intravenous thrombolysis, and reconstructed the images for dynamic CTA in the Second Affiliated Hospital, Zhejiang University School of Medicine from June 2009 to October 2013. The total extent and flow speed of collateral flow based on dynamic CTA images of these patients were evaluated. The scores of National Institute of Health stroke scale (NIHSS) in different collateral flows were compared with repeated measuring. The nonparametric Spearman's rank correlation was used to assess the relationship between collateral flow and modified Rankin scale (mRS) at 3 months after thrombolytic therapy. RESULTS: Compared with the poor collateral flow group, patients with good collateral flow had lower NIHSS at 1 month after thrombolysis (4.7±5.0 vs 25.1±15.1, P=0.001) and higher reperfusion percentage (69%±32% vs 23%±54%, P=0.044). The total condition score of collateral flow was positively correlated with mRS at 3 months after treatment (r=0.450, P=0.001). CONCLUSION: Acute ischemic stroke patients with good collateral flow after intravenous thrombolysis have a better outcome. The dynamic CTA can be used to evaluate the collateral flow and to predict clinical outcomes in patients with acute ischemic stroke after thrombolysis therapy.

[Impact of atrial fibrillation on clinical outcome in patients with acute ischemic stroke undergoing thrombolytic therapy].

OBJECTIVE: To investigate the impact of atrial fibrillation (AF) on clinical outcomes in patients with acute ischemic stroke undergoing thrombolytic therapy. METHODS: The clinical data of 330 patients with acute ischemic stroke who received intravenous recombinant tissue plasminogen activator (rt-PA) therapy in the Second Affiliated Hospital, Zhejiang University School of Medicine between June 2009 and August 2013 were reviewed. Clinical outcomes in AF and non-AF groups were evaluated by univariate and multivariate analysis. Favorable outcome was defined as a modified Rankin Scale (mRS) 0-2 on day 90. Hemorrhagic transformation (HT) was classified as hemorrhagic infarction (HI) and parenchymal hematoma (PH) within the first 24h according to ECASS II criteria. Hypoperfusion and severe hypoperfusion were defined as Tmax >6 s and >8 s, respectively. The rate of reperfusion was compared between AF and non-AF groups. RESULTS: Among 330 patients, 137(41.5%) had AF. Compared with non-AF patients, patients with AF were older [(71.7±11.5)y vs (63.4±13.2)y, P<0.001], had higher baseline National Institutes of Health Stroke Scale [IQR, 13(8-16) vs 9(5-15), P<0.001], higher rate of HT(HI: 28.5% vs 17.1%, P=0.015; PH: 13.9% vs 4.1%, P=0.002), and lower rate of favorable outcome (41.5% vs 58.0%, P=0.005) at d 90. After adjustment, AF was not a risk factor for favorable outcome (OR=0.920, 95%CI:0.533-1.586; P=0.763) and mortality (OR=1.381, 95%CI:1.096-1.242; P=0.466) on day 90. AF was also not associated with HI (OR=1.676, 95%CI: 0.972-3.031; P=0.088), but it increased the rate of PH (OR=3.621, 95%CI: 1.403-9.344; P=0.008). Among 94 patients with pre- and post-thrombolytic perfusion-weighted image, AF was not associated with increased rate of reperfusion for hypoperfusion (Tmax >6 s, OR=1.12, 95%CI: 0.35-3.63, P=0.849), but was correlated with increased rate of reperfusion for severe hypoperfusion (Tmax>8 s, OR=10.57, 95%CI:1.16-96.50, P=0.037). CONCLUSION: The presence of AF has no independent impact on neurological outcome in thrombolytic patients with acute ischemic stroke. It is associated with increased reperfusion rate of more severe hypoperfusion area and higher frequency of PH.

[Risk factors of hemorrhagic transformation in different locations and its relation to clinical outcomes of patients with acute ischemic stroke following intravenous thrombolysis].

OBJECTIVE: To investigate the risk factors of hemorrhagic transformation (HT) in different cerebral regions and to explore its relation to clinical outcomes of patients with acute ischemic stroke after intravenous thrombolysis therapy. METHODS: The clinical, laboratory, and radiological data of 292 consecutive acute ischemic stroke patients undergoing intravenous thrombolysis therapy in Second Affiliated Hospital, Zhejiang University School of Medicine from June 2009 to May 2013 was retrospectively analyzed. Deep HT was defined as HT located in basal ganglia, internal capsule, external capsule and thalamus, otherwise the lesion was defined as non-deep HT. Patients were divided into 3 groups [Deep HT(n=47), non-deep HT(n=82), non HT(n=8)] and the differences in clinical and demographic characteristics were compared by using one-way analysis of variance and Ξ2-test. Multivariable logistic regression models were used to determine the independent risk factors of HT in different cerebral regions and clinical outcomes. RESULTS: Age, baseline National Institutes of Health Stroke Scale (NIHSS) score, baseline systolic blood pressure and the frequency of atrial fibrillation were different among three groups. Logistic regression analysis revealed that baseline NIHSS score (OR=1.126, 95%CI:1.063-1.193, P<0.001) and baseline systolic blood pressure (OR=0.982, 95%CI:0.967-0.998, P=0.020) were independent risk factors of deep HT. Multivariate analysis also found that deep HT was an independent predictor of functional outcome after thrombolysis (OR=0.291, 95%CI:0.133-0.640, P=0.002). CONCLUSION: Baseline NIHSS score and systolic blood pressure are predictors for deep hemorrhagic transformation, which indicates the poor functional outcome of patients with acute ischemic stroke following thrombolytic therapy.

Toxic encephalopathy caused by occupational exposure to 1, 2-Dichloroethane.

This study describes the clinical and neuroimaging features of five patients with 1, 2-Dichloroethane (DCE) toxic encephalopathy. From January 1st 1998 to June 30th 2009, five patients who were subsequently diagnosed with DCE toxic encephalopathy were admitted to our hospital. All were female workers who had been in contact with DCE and subsequently had had seizures or symptoms of intracranial hypertension, including headache, nausea, and vomiting. The cranial MRI showed extensive brain edema in either the subcortical white matter, bilateral globus pallidus, and cerebellar nucleus dendatus, or the cortices. Of the five patients in the study, three had vasogenic edema, one had cytotoxic edema, and one had both types of edema. Following treatment with steroids and mannitol for 3 to 10 weeks, all patients made either a partial or complete recovery. The imaging findings were resolved on a follow-up MRI. It is clear that occupational exposure to DCE can cause severe toxic encephalopathy. Moreover, extensive brain edema, secondary to blood-brain barrier damage or neuronal injury, is the major neuroimaging feature and the cause of clinical manifestations. Early diagnosis and prompt treatment leads to a good outcome.