BACKGROUND: Transcranial Doppler ultrasonography that is aimed at residual obs tructive intracranial blood flow may help expose thrombi to tissue plasminogen a ctivator (t-PA). Our objective was to determine whether ultrasonography can saf ely enhance the thrombolytic activity of t-PA. METHODS: We treated all patients who had acute ischemic stroke due to occlusion of the middle cerebral artery wi th intravenous t-PA within three hours after the onset of symptoms. The patient s were randomly assigned to receive continuous 2-MHz transcranial Doppler ultra sonog(raphy the target group) or placebo(the control group). The primary combine d end point was complete recanalization as assessed by transcranial Doppler ultr asonography or dramatic clinical recovery. Secondary end points included recover y at 24 hours, a favorable outcome at three months, and death at three months. R ESULTS: A total of 126 patients were randomly assigned to receive continuous ult rasonography(63 patients) or placebo(63 patients). Symptomatic intracerebral hem orrhage occurred in three patients in the target group and in three in the contr ol group. Complete recanalization or dramatic clinical recovery within two hours after the administration of a t-PA bolus occurred in 31 patients in the target group(49 percent), as compared with 19 patients in the control group(30 percent ; P=0.03). Twenty-four hours after treatment of the patients eligible for follo w-up, 24 in the target group(44 percent) and 21 in the control group (40 percen t) had dramatic clinical recovery(P=0.7). At three months, 22 of 53 patients in the target group who were eligible for follow-up analysis (42 percent) and 14 o f 49 in the control group(29 percent) had favorable outcomes (as indicated by a score of 0 to 1 on the modified Rankin scale)(P=0.20). CONCLUSIONS: In patients with acute ischemic stroke, continuous transcranial Doppler augments t-PA-indu ced arterial recanalization, with a nonsignificant trend toward an increased rat e of recovery from stroke, as compared with placebo. Copyright. BACKGROUND: Transcranial Doppler ultrasonography that is aimed at residual obs tructive intracranial blood flow may help expose thrombi to tissue plasminogen a ctivator (t-PA). Our objective was to determine whether ultrasonography can saf ely enhance the thrombolytic activity of t-PA. METHODS : We treated all patients who had acute ischemic stroke due to occlusion of the middle cerebral artery wi th intravenous t-PA within three hours after the onset of symptoms. The patient s were randomly assigned to receive continuous 2-MHz transcranial Doppler ultra sonog ( raphy the target group) or placebo (the control group). The primary combine d end point was complete recanalization as assessed by transcranial Doppler ultr asonography or dramatic clinical recovery. Secondary end points included recover y at 24 hours, a favorable outcome at three months , and death at three months. R ESULTS: A total of 126 patients were randomly assigned to receive continuous ult rasonography (63 patients) or placeb Symptomatic intracerebral hemiorrhage occurred in three patients in the target group and in three in the contr ol group. Complete recanalization or rapid clinical recovery within two hours after the administration of a t-PA bolus occurred in 31 patients in The target group (49 percent), as compared with 19 patients in the control group (30 percent; P = 0.03). Twenty-four hours after treatment of the patients eligible for follo w-up, 24 in the target group (three per cent) and 21 in the control group (40 percen t) had dramatic clinical recovery (P = 0.7). At three months, 22 of 53 patients in the target group who were eligible for follow-up analysis (42 percent) and 14 of 49 in the control group (29 percent) had favorable outcomes (as indicated by a score of 0 to 1 on the modified Rankin scale) (P = 0.20). CONCLUSIONS: In patients with acute ischemic stroke, continuous transcranial Doppler augments t- PA- indu ced arterial recanalization, with a nonsignificant trend toward an increased rat e of recovery from stroke, as compared with placebo. Copyright.