MRI of acute post-ischemic cerebral hemorrhage in stroke patients: diagnosis with T2*-weighted gradient-echo sequences

The use of T2*-weighted sequences has been advocated for early differentiat ion between hematoma and ischemia in patients with acute stroke. Early hemo rrhagic transformation of ischemic stroke is an adverse event which may occ ur under treatment and may impair the prognosis: our aim is to evaluate the ability of T2*-weighted gradient-echo sequence (T2* GRE) to detect post-is chemic cerebral hemorrhage. The imaging procedure included: (1) baseline CT scan at admission. (2) MRI performed within 24 h of therapy onset includin g: (a) dual fast spin echo T2 sequence, (b) axial isotropic echoplanar diff usion-weighted imaging sequence, (c) conventional T2* GRE, and (d) 3D TOF t urbo MRA. Post-ischemic cerebral hemorrhage was diagnosed if T2* GRE detect ed a focal intraparenchymal area of signal loss. The diameter of this lesio n had to be more than 5 mm in order to eliminate past microbleeds. (3) Pati ents who showed an early suspicion of bleeding on MRI promptly had a second CT scan, and, if this one was negative for bleeding, another CT scan was p erformed 1 day later. All the other patients had a control CT scan during t he first week. Forty-five consecutive patients have been included. T2* GRE showed intracranial bleeding in seven. The diagnosis of post-ischemic cereb ral bleeding was confirmed by CT in all patients. Control CT scans did not reveal any post-ischemic cerebral hemorrhage in patients with negative MRI. In one case, hemorrhage was seen earlier on MRI than on CT scan. In conclu sion, T2* GRE appeared to be at least as efficient as CT scan in the detect ion of early post-ischemic cerebral hemorrhage.