Fig. 5. Intra-operative acidic margin-guided surgery improves surgical prognosis and minimizes functional deficits. (A) In vivo MR images of a rat brain bearing C6 rat orthotopic allografts before and at selected days post iAM-guided, iSM-guided and pSM-guided surgery. Tumors with hyper-intensive signals in the preoperative T2W-MR images were delineated by yellow dotted lines. The recurrent tumor was indicated by a white arrow. Kaplan–Meier survival (B) and neurological testing scores (C) after corresponding surgical intervention. Data were presented as mean ± S.D. (n = 5). **p < 0.01 between the iAM-, iSM-guided strategy and pSM-guided surgery. ns, no significant difference. In panel E, **p < 0.01 and *p < 0.05 between the iAM- and iSM-guided groups on day 3 and 7. iAM-guid.: intra-operative acidic margin guided surgery; iSM-guid.: intra-operative structure margin guided surgery; pSM-guid.: preoperative structural margin guided surgery. CE-T1W: contrast enhanced T1-weighted.