Background: Tandem occlusion of the arteries at the extracranial and intracranial segments is a unique cause of ischemic stroke and is often associated with a poor prognosis. Although tandem occlusion is occasionally found during intra-arterial thrombolysis (IAT), as of yet no clear therapeutic strategy has been elucidated. Methods: After identifying distal intradural (DIL) and proximal extradural lesions (PEL) as well as the collateral state and clot burden, IAT was performed primarily targeting DIL by navigation of the microcatheter through the PEL or a collateral pathway. Results: Among 147 consecutive patients who were treated with IAT for hyperacute ischemic stroke, 13 (11.4%) were identified to have tandem occlusion as the cause of stroke. Navigation of a microcatheter through occluded PEL (internal carotid artery/vertebral artery) or a collateral pathway (anterior communicating artery) to the DIL was successful in 9 patients. Of them, recanalization of the DIL could be achieved in 8 (89%). The overall recanalization rate among all patients with tandem occlusion was (62%, 8/13). A good functional outcome (modified Rankin score ≤2) at 3 months was noted in 6 patients (46.2%). Conclusions: Tandem occlusion may be successfully managed by strategic thrombolysis of the DIL as the primary therapeutic target for IAT. By this strategy, the ischemic brain could be effectively and rapidly perfused.

Simple mechanical-based thrombolysis using microwire and microcatheter with adjuvant low-dose i.a. UK is safe and effective in achieving recanalization with good long-term outcome.

This paper proposes a second-order differential microphone array (DMA) that can continuously steer in the main lobe direction. First, a general response of the second-order DMA is derived as a linear combination of a monopole and dipoles. Nine- and seven-microphone systems are proposed to realize continuous steering of the second-order DMA. The proposed system synthesizes the steered beam pattern without requiring the phase shifter by using back-to-back cardioids. Simulation results show that the nine-microphone configuration yields a nearly constant and high white noise gain, but the seven-microphone configuration has the practical advantage that it requires fewer microphones.

No abstract