After 10 min, we examined the contralateral hemisphere with the same protocol. We selected ROIs in the contralateral MCA territory, which corresponded in size, shape and localization to the Galunisertib mw ischemic ROIs (Fig. 3). Parameters of refill kinetics (A, β and the product A × β) were extracted from each ROI for statistical analysis. To analyze the potential relationship between MCA flow velocity and the parameters

of refill kinetics, we subdivided patients in two groups: patients with persisting MCA pathology defined by COGIF grades of 3 or lower, and patients with symmetrical or increased MCA flow (COGIF grade 4). We examined 31 patients (17 male, 14 female, mean age 68.3 ± 13.4) who were admitted to our stroke unit with acute ischemic stroke in the MCA territory (Table 1). 58% of patients were treated with intravenous thrombolysis. At the time point of examination, TCCD showed a persistent pathological flow pattern of

the ipsilateral MCA (COGIF grades 0–3) in 21/31 (67.7%) patients. Pathological flow patterns were more frequent among patients who were not VX-809 mw treated with tPA (11/13 vs. 10/18, p = 0.08). Rt-UPI showed significantly lower values of the refill parameter β in the ischemic area compared to the contralateral MCA territory (β (1/s): 0.75 ± 0.41 vs. 1.05 ± 0.51, p < 0.05). The difference between ischemic and contralateral ROIs was more prominent in patients with persisting MCA obstruction (n = 21; β (1/s): 0.61 ± 0.31 vs. 1.01 ± 0.53, p = 0.005). Correspondingly, in patients with symmetrical or increased ipsilateral MCA SB-3CT flow, β values were not significantly different between both hemispheres (n = 10; β (1/s): 1.04 ± 0.47 vs. 1.14 ± 0.49, p = n.s.). There was no significant difference between β values of the ischemic tissue of patients treated with tPA and those who did not receive systemic thrombolysis (β (1/s): 0.72 ± 0.32 vs. 0.78 ± 0.53, p = n.s.). For the plateau of acoustic intensity (A) and the product of A and β

(A × β), there was a high interindividual variance of the values, resulting in no significant difference between ischemic or contralateral healthy tissue in any group of patients ( Table 2). This study investigated the feasibility of rt-UPI with refill kinetics to assess perfusion deficits related to persistent or already recanalized arterial obstruction in acute MCA stroke patients. The parameter β, which represents the slope factor of the exponential function of refill kinetics, shows overall significant differences between ischemic and healthy tissue. This finding was more pronounced in patients with COGIF grades 0–3 and was absent in COGIF grade 4. The parameters A and the product A × β showed high standard deviations in our study, which resulted in a lack of significance between ischemic and non-ischemic tissue for these parameters.