Background and Purpose-Collaterals sustain the penumbra before recanalization and offset infarct growth, yet the influence of baseline collateral flow on recanalization after endovascular therapy remains relatively unexplored. Methods-We analyzed consecutive patients who received endovascular therapy for acute cerebral ischemia from 2 distinct study populations.

The time-dependent effect of transcranial direct current stimulation (tDCS) on working memory was investigated by applying anodal stimulation over the left prefrontal cortex. This single-blind, sham-controlled crossover study recruited 15 healthy participants. A three-back verbal working-memory task was performed before, during, and 30 min after 1 mA anodal or sham tDCS. Anodal tDCS, compared with sham stimulation, significantly improved working-memory performance. Accuracy of response was significantly increased after 20 min of tDCS application, and was further enhanced after 30 min of stimulation. This effect was maintained for 30 min after the completion of stimulation. These results suggest that tDCS at 1 mA enhances working memory in a time-dependent manner for at least 30 min in healthy participants.

Background and Methods-To assess the precise mechanisms of stroke in cancer patients, we analyzed the data for cancer patients with acute ischemic stroke registered from 6 centers in South Korea. Clinical features, risk factors, diffusion-weighted imaging lesion patterns, and laboratory findings including D-dimer levels were compared between patients with conventional stroke mechanisms (CSMs) and cryptogenic group. Results-A total of 161 patients were included in this study: 97 (60.2%) patients in the CSM group and 64 (39.8%) in the cryptogenic group. Patients in the CSM group were older and vascular risk factors were more prevalent than in the cryptogenic group. Diffusion-weighted imaging patterns of multiple lesions involving multiple arterial territories were observed more frequently in the cryptogenic group than in the CSM group. In addition, levels of the D-dimer were higher in the cryptogenic group than in the CSM group (11.5Ϯ14.6 versus 3.6Ϯ10.3 g/dL). In multivariate analysis, the diffusion-weighted imaging lesion pattern of multiple vascular territories (odds ratio, 11.2; 95% CI, 3.74 to 33.3), and D-dimer levels of Ͼ1.11 g/dL (odds ratio, 10.6; 95% CI, 3.29 to 33.8) were associated independently with the cryptogenic group. Conclusions-Stroke outside of CSM occurred in a large number in cancer patients. In stroke patients with cancer, D-dimer levels and diffusion-weighted imaging lesion patterns may be helpful in early identification of non-CSMs (especially coagulopathy associated with cancer) and possibly in guiding preventive strategies for stroke. (Stroke. 2010;41:798-801.)