London, United Kingdom 2013 Poster Session Red Cerebrovasc Dis 2013; 35 (suppl 3)1-854 417 247 Brain imaging Dural transcranial direct current stimulation over primary motor cortex during fMRI K.L. Joa1, J.H. Min2, W.H. Kim3, Y.I. Shin4 Pusan National University Yangsan Hospital, Yang-san si, SOUTH KOREA1, Pusan National University Yangsan Hospital, Yang-san si, SOUTH KOREA2, Pusan National University Yangsan Hospital, Yang-san si, SOUTH KOREA3, Pusan National University Yangsan Hospital, Yang-san si, SOUTH KOREA4 Background: Transcranial direct current stimulation (tDCS) has been reported as an effective meth-od for manipulating human brain exciatbility through continuous application of a weak direct cur-rent on the scalp. The effect of tDCS varies depending on the polarity of the electrode; anodal polar-ization increases cortical excitability, whereas cathodal polarization decreases it. Also, simultaneous dual tDCS produced an additive effect to facilitate motor performance in the hand. In this study, we observed modulation of motor networks induced by dual tDCS in healthy subjects using functional MRI (fMRI). Methods: Twelve right handed healthy participants (Mean age: 25.6 years, 6 male) underwent two stimulation conditions: 1) Real dual-hemisphere – with anodal tDCS over right primary motor cor-tex (M1) 2) Sham tDCS. Before and after tDCS, fMRI were performed while both finger tapping task were performed in a conventional block design. Participants performed a finger-sequencing task with the non-dominant hand before and after real and sham stimulation outside MR scanner. Results: In the real tDCS session, there was similar activation pattern before and after stimulation during right hand task. When fMRI images between the real and sham tDCS sessions were com-pared, there was no significant interaction in motor network. In the real tDCS session, there was increased activation in right M1 and decreased activation in left M1 and both SMA during left hand task. When fMRI images between the real and sham tDCS sessions were compared, the real tDCS session showed significantly increased activation in the both SMA and left M1 in motor network after applying tDCS. After real tDCS, there was significant improvement in reaction time and move-ment accuracy in finger-sequencing task (p<0.05). Conclusions: Simultaneously dual tDCS over bilateral M1 modulated functional motor networks during motor task. Effective modulation of functional networks by dual tDCS might be a determi-nant to obtain functional improvements in healthy persons by direct or distant effect. 248 Brain imaging Early hyperperfusion in acute ischemic stroke: Is it benign? J.E. Fugate1, D.F. Kallmes2, A.A. Rabinstein3 Mayo Clinic, Rochester, USA1, Mayo Clinic, Rochester, USA2, Mayo Clinic, Rochester, USA3 Background: Computed tomography perfusion (CTP) scans are valuable in acute stroke assessments because of the ability to identify potentially salvageable brain tissue (ischemic penumbra) and to delineate irreversibly damaged brain (core infarct). Studies have shown that the area of final brain infarction corresponds best with regions of hypoperfusion as manifested by very reduced cerebral blood flow. Methods: Case series from a single center academic medical center Results: Four adult patients (median age 64 years) with a median NIHSS of 19 (range 16-21) who presented for evaluation of acute ischemic stroke. All patients received intravenous rtPA, and when clinical deficits persisted, brain CTP was obtained. CTP was obtained at a median of 189 minutes after symptom onset (range 125-343 minutes). All patients underwent endovascular stroke therapy via intraarterial mechanical thrombectomy. A reperfusion grade of TICI 2b was achieved in three patients and TICI 2a in one. Two patients had intracranial hemorrhage. All patients had regions of hyperperfusion on CTP that ultimately became either part of the ultimate core infarction or a nidus of hemorrhagic transformation. Conclusion: In patients with acute ischemic stroke, areas of early hyperperfusion on CTP may not be benign and may include regions of brain that ultimately become infarct core despite successful and timely recanalization therapy.
Karger_ESC London_2013
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