22. European Stroke Conference Brain imaging (PO 221 - 249) 221 Brain imaging Simple MR angiography method can assess hemodynamic impairment in patients with carotid artery occlusion. K.H. Choi1, J.T. Kim2, S.H. Lee3, M.S. Park4, B.C. Kim5, M.K. Kim6 Department of Neurology, Chonnam National University Hospital, Gwangju, SOUTH KO-REA1, Department of Neurology, Chonnam National University Hospital, Gwangju, SOUTH KOREA2, Department of Neurology, Chonnam National University Hospital, Gwangju, SOUTH KOREA3, Department of Neurology, Chonnam National University Hospital, Gwangju, SOUTH KOREA4, Department of Neurology, Chonnam National University Hospital, Gwangju, SOUTH KOREA5, Department of Neurology, Chonnam National University Hospital, Gwangju, SOUTH KOREA6 Background: Visualization of the middle cerebral artery (MCA) flow on single-slab 3D time-of-flight (TOF) MR angiography (MRA) can reflect blood flow velocity. The velocity in the middle cerebral artery (MCA) may correlate with cerebrovascular reactivity (CVR) to acetazolamide, which can be used to assess hemodynamic impairment. The purposes of the present study were to compare the signal intensity of the MCA on MRA versus CVR quantified by perfusion single-photon emis-sion 402 © 2013 S. Karger AG, Basel Scientific Programme CT (SPECT). Methods: This study included 42 patients aged 55 to 85 years (mean age, 67 years) with occlusion in the cervical portion of the internal carotid artery (ICA). Signal intensity of the MCA in the intra-cranial MRA was visually classified into the 4 grades according to the ability to visualize the MCA. SPECT-CVR was also calculated by measuring cerebral blood flow before and after acetazolamide challenge. Using the same method, we studied 10 subjects without ICA and MCA occlusion to ob-tain control values. Results: CVR was significantly lower in patients with MRA grade B, C, D than in those with MRA grade A (P <0.01). When the reduced signal intensity of the MCA on MRA was defined as abnormal, and when a CVR less than the mean 2 SD of control subjects was defined as reduced, MRA grading resulted in a 83.2% sensitivity and 77.8% specificity, with 81.0% positive predictive and 91.7% neg-ative- predictive values to detect reduced CVR. Conclusions: Our study demonstrates that a simple MRA method can assess hemodynamic impair-ment with a high positive and negative predictive value. Therefore, the results of this study suggest that the patients of ICA occlusion with the reduced signal intensity of the MCA should be carefully managed. 222 Brain imaging Hyperdense MCA sign revisited: Utility of density and burden assessment in estimating stroke etiology and prognosis after thrombolysis E.M. Arsava1, O. Kursun2, E. Akpinar3, B. Erbil4, M.A. Topcuoglu5 Department of Neurology, Faculty of Medicine, Hacettepe University, Ankara, TURKEY1, Neurology Clinic, Ankara Numune Education and Research Hospital, Ankara, TURKEY2, Depart-ment of Radiology, Faculty of Medicine, Hacettepe University, Ankara, TURKEY3, Department of Emergency Medicine, Faculty of Medicine, Hacettepe University, Ankara, TURKEY4, Department of Neurology, Faculty of Medicine, Hacettepe University, Ankara, TURKEY5 Background: Hyperdense MCA sign (HMCAS) is a well-established indicator of proximal MCA occlusion in the setting of ischemic stroke. In this study, we assessed the value of HMCAS density quantification and HMCAS burden in predicting stroke etiology and prognosis after thrombolysis. Methods: The density of HMCAS was quantified by determination of the maximum pixel-wise Hounsfield Unit (HU) in 88 patients with acute MCA proximal segment occlusion, 12 patients with acute posterior circulation stroke and 44 non-stroke control subjects. All stroke cases were subjected to intravenous or intraarterial thrombolysis. The effect of presence of HMCAS, absolute density of HMCAS, side to side HU ratio and difference, and MCA hyperdensity burden score (MCAHBS) on stroke etiology, early recovery and long-term prognosis were determined by univariate and multivar-iate analyses. Results: In comparison with HMCAS-negative cases, acute stroke cases with HMCAS (37.5%) had higher mean thrombus HU on the symptomatic side (53.4±6.9 vs. 44.6±6.2; p=<0.01). ROC analysis demonstrated satisfactory AUC values for absolute HU (0.904), HU ratio (0.846) and HU differ-ence (0.862) for determination of HMCAS. The optimal operating points were >45 for absolute HU, >1.10 for HU ratio and >4 for HU difference. None of the HU indices had any discriminative value for stroke etiology. Multiple regression analysis showed previously defined CTA based clot burden score (p<0.01) and the new CT-based MCAHBS (p=0.02) as significant predictors for early dramatic recovery, while age (p<0.01) and baseline NIHSS (p=0.02) were the only determinants of 3-month functional outcome. Conclusions: The extent of hyperdensity within the MCA thrombus, but not ist density, was predic-tive of early clinical response to thrombolysis. Neither HMCAS numeric indices, nor ist extent had value in predicting stroke etiology or long-term prognosis.
Karger_ESC London_2013
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