Nonlacunar Ischemic Stroke Research Articles

Clinical and Radiological Correlates of Reduced CBF Measured Using MRI

11 Background and purpose Methods for determining CBF using IV bolus tracking MRI have recently become available. Reduced apparent diffusion coefficient (ADC) values of brain tissue are associated with reductions in regional cerebral blood flow (rCBF). We studied the clinical and radiological features of patients with severe reductions of rCBF on MRI and analysed the relationship between reduced rCBF and ADC. Methods We studied patients with non-lacunar acute ischemic stroke in whom PWI and DWI MRI were performed within 7 hours after symptom onset. A PWI>DWI mismatch of >20% was required. Maps of rCBF, cerebral blood volume (rCBV) and mean transit time (rMTT) were generated after deconvoluting the measured concentration-time curve with the arterial input function using singular value decomposition. The ischemic lesion was outlined on the MTT map and the region of interest (ROI) transferred to the rCBF and rCBV map. ADC-maps were calculated. ADC lesions were defined as regions with ADC values ≤ 550 μm m2/sec. We compared the characteristics of patients with ischemic lesions that had a relative CBF of 50%. Characteristics analysed included age, time to MRI, baseline NIHSS, mean ADC, DWI lesion volume, PWI lesion volume and absolute mismatch volume. Results Fifteen patients with an initial PWI>DWI mismatch of >20% were included. Ten had lesions with rCBF of >50% (median 60%) and five patients had rCBF of μ mm2/sec, p=0.028), larger DWI volumes (median 75.6 cm 3 versus 8.6 cm 3 , p=0.001) and larger PWI lesions as defined by the MTT volume (median 193 cm 3 versus 69 cm 3 , p=0.028) and more severe baseline NIHSS scores (median 18 versus 9, p=0.019). The rMTT and rCBV of the lesions were similar in both groups, as were the age, the absolute mismatch volume and the time from symptom onset to MRI. Conclusion These data indicate that ischemic lesions with severe CBF reductions, measured with new MRI techniques, are associated with a lower mean ADC, larger DWI and PWI lesion volumes and a higher NIHSS score.

Clinical and Radiological Correlates of Reduced CBF Measured Using MRI

11 Background and purpose Methods for determining CBF using IV bolus tracking MRI have recently become available. Reduced apparent diffusion coefficient (ADC) values of brain tissue are associated with reductions in regional cerebral blood flow (rCBF). We studied the clinical and radiological features of patients with severe reductions of rCBF on MRI and analysed the relationship between reduced rCBF and ADC. Methods We studied patients with non-lacunar acute ischemic stroke in whom PWI and DWI MRI were performed within 7 hours after symptom onset. A PWI>DWI mismatch of >20% was required. Maps of rCBF, cerebral blood volume (rCBV) and mean transit time (rMTT) were generated after deconvoluting the measured concentration-time curve with the arterial input function using singular value decomposition. The ischemic lesion was outlined on the MTT map and the region of interest (ROI) transferred to the rCBF and rCBV map. ADC-maps were calculated. ADC lesions were defined as regions with ADC values ≤ 550 μm m2/sec. We compared the characteristics of patients with ischemic lesions that had a relative CBF of <50% to the contralateral hemisphere to patients with lesions that had relative CBF of >50%. Characteristics analysed included age, time to MRI, baseline NIHSS, mean ADC, DWI lesion volume, PWI lesion volume and absolute mismatch volume. Results Fifteen patients with an initial PWI>DWI mismatch of >20% were included. Ten had lesions with rCBF of >50% (median 60%) and five patients had rCBF of <50% (median 27.7%). Patients with rCBF <50% had lower ADC values (median 431 μmm2/sec versus 506 μ mm2/sec, p=0.028), larger DWI volumes (median 75.6 cm 3 versus 8.6 cm 3 , p=0.001) and larger PWI lesions as defined by the MTT volume (median 193 cm 3 versus 69 cm 3 , p=0.028) and more severe baseline NIHSS scores (median 18 versus 9, p=0.019). The rMTT and rCBV of the lesions were similar in both groups, as were the age, the absolute mismatch volume and the time from symptom onset to MRI. Conclusion These data indicate that ischemic lesions with severe CBF reductions, measured with new MRI techniques, are associated with a lower mean ADC, larger DWI and PWI lesion volumes and a higher NIHSS score.

Is early ischemic lesion volume on diffusion-weighted imaging an independent predictor of stroke outcome? A multivariable analysis.

The heterogeneity of stroke makes outcome prediction difficult. Neuroimaging parameters may improve the predictive value of clinical measures such as the National Institutes of Health Stroke Scale (NIHSS). We investigated whether the volume of early ischemic brain lesions assessed with diffusion-weighted imaging (DWI) was an independent predictor of functional outcome. We retrospectively selected patients with nonlacunar ischemic stroke in the anterior circulation from 4 prospective Stanford Stroke Center studies evaluating early MRI. The baseline NIHSS score and ischemic stroke risk factors were assessed. A DWI MRI was performed within 48 hours of symptom onset. Clinical characteristics and early lesion volume on DWI were compared between patients with an independent outcome (Barthel Index score >/=85) and a dependent outcome (Barthel Index score <85) at 1 month. A logistic regression model was performed with factors that were significantly different between the 2 groups in univariate analysis. Sixty-three patients fulfilled the entry criteria. One month after symptom onset, 24 patients had a Barthel Index score <85 and 39 had a Barthel Index score >/=85. In univariate analysis, patients with independent outcome were younger, had lower baseline NIHSS scores, and had smaller lesion volumes on DWI. In a logistic regression model, DWI volume was an independent predictor of outcome, together with age and NIHSS score, after correction for imbalances in the delay between symptom onset and MRI. DWI lesion volume measured within 48 hours of symptom onset is an independent risk factor for functional independence. This finding could have implications for the design of acute stroke trials.

Immediate Anticoagulation With Heparin for First-Ever Ischemic Stroke in the Carotid Artery Territories Observed Within 5 Hours of Onset

To evaluate the safety and possible efficacy of heparin sodium anticoagulation within 5 hours of the onset of first-ever nonlacunar ischemic strokes in the internal carotid artery territories. Pilot study, prospective and open. Inpatient stroke unit. Of 360 stroke patients observed during 13 months, 45 (12.5%) were included in the study. Heparin sodium was administered intravenously, starting with a bolus of 10,000 U, followed by continuous infusion over 4 days at a rate adjusted to maintain an activated partial thromboplastin time ratio between 2 and 2.5. The mean interval from stroke to treatment was 197 minutes. Two patients had cerebral hemorrhage, one of which was fatal. None had extracranial major bleeding, while six had minor bleeding. The conditions of 23 patients improved, 16 patients were stable, and six patients worsened by day 1, while 29 patients improved, eight patients were stable, and eight patients worsened by day 7. Six patients died by the first month and five more by the sixth month. Twenty-one patients were self-sufficient, both at 1 and 6 months. Hemorrhagic complications were unrelated to any investigated factor. Multivariate analysis indicated that short-term outcome was predicted only by infarct size (P < .0001) and long-term outcome by infarct size (P = .002) and large vessel status (P = .0235). Our study suggests that immediate heparin treatment for ischemic carotid stroke is feasible and generally safe and that patients whose conditions improve are those with smaller infarct size and no evidence of large vessel obstruction.

Diagonal earlobe creases and ischemic stroke: Preliminary report

Diagonal earlobe creases are associated with coronary arterial disease, cardiac morbidity and mortality, and all-cause mortality. We studied the influence of earlobe creases on the incidence of ischemic stroke as well as the relationship between earlobe creases and gender, coronary arterial disease, hypertension, diabetes mellirus, and hypercholesterolemia. Data were obtained prospectively from the medical records of 116 patients with ischemic stroke and 232 age- and gender-matched patients without ischemic stroke. All patients were seen in neurological consultation and were examined for the presence of earlobe creases. In the total group of 348 patients, earlobe creases were significantly related to advancing age. In those with ischemic stroke, earlobe creases were significantly related to coronary arterial disease, diabetes mellitus, and nonlacunar ischemic stroke. The cumulative incidences of coronary arterial disease, hypertension, diabetes mellitus, and hypercholesterolemia were also significantly higher in those patients with earlobe creases who also had ischemic stroke. When controlled for coronary arterial disease, earlobe creases, in those with ischemic stroke, continued to be significantly related to nonlacunar ischemic stroke.

Cytokines and endothelial cell biology

Ce travail resume les etudes qui ont permi la caracterisation de l'action specifique des cytokines sur les cellules endotheliales. Les cytokines agissent aussi sur l'endothelium dans des cas pathologiques cites dans cet expose