Differences between head CT and MRI for selecting patients for intravenous rt-PA during hyperacute brain infarction. Comparative study of intracranial bleeding complications and prognosis

The objective of this study was to investigate the differences in usefulness between head CT and MRI for selecting patients for intravenous injection of recombinant tissue plasminogen activator (rt-PA) during hyperacute brain infarction. Of a total of 1280 brain infarction patients who were admitted from October 2005 to March 2009, 45 patients (33 men and 12 women with an average age of 69.2±11.6 years) received intravenous rt-PA. Of these, 16 patients in whom only head CT was performed (593 inpatients from October 2005 to March 2007, CT standard group, 11 men and 5 women, average age 67.4±15.4 years) and 29 patients in whom head CT and MRI were performed (687 inpatients from April 2007 to March 2009, MRI standard group, 21 men and 7 women, average age 70.1±9.0 years) were studied. The median National Institutes of Health Stroke Scale (NIHSS) scores immediately before intravenous rt-PA for the CT and MRI standard groups were 19 and 11, respectively; disease severity was lower for the MRI standard group. Three months later, the modified Rankin Scale (mRS) score for the MRI standard group (0-1: 31%, 2-3: 38%, 4-5: 24%, and 6: 12%) was better than for the CT standard group (0-1: 25%, 2-3: 25%, 4-5: 38%, and 6: 12%). The frequency of symptomatic intracranial hemorrhage was lower for the MRI standard group (6.9%) than for the CT standard group (18.8%). However, there was no statistical difference in the prognosis and incidence of intracranial hemorrhage between the 2 groups, due to the small number of cases. When selecting patients for intravenous rt-PA, brain infarction improved more, prognosis was better three months later, and the frequency of symptomatic intracranial hemorrhage was lower among patients selected based on MRI standards than among those selected based on CT standards. (author)