Evaluation of the ischemic lesion volume with T2-weighted images (T2WI). BMSCs or PMSCs were intravenously injected immediately after the initial MRI scanning (6 h after MCAO). Images obtained 6 h, and 1, 3, and 7 days MCAO in medium-injected (A1–4), BMSC-treated (B1–4), and PMSC-treated group (C1–4). Summary of lesion volumes evaluated with T2WI in each groups (D). Scale bar = 3 mm. *p < 0.05.