[Comparison between x-ray computed tomography and magnetic resonance imaging after transient ischemic accidents]

We studied 18 patients with transient ischemic accidents (TIA) and normal CT scan during the first 24 hours. MRI was performed 9 days later on average. MRI revealed abnormalities in 10 patients (56 p. 100), but only 5 of them (27 p. 100) had lesions corresponding to TIAs, and in every case these were in the carotid territory. In the 7 patients with clinical signs of TIA in the vertebro-basilar territory, MRI was always negative. In 5 patients (27 p. 100), MRI showed abnormalities that were unrelated to TIA. This study suggests that MRI is of limited value in detecting brain tissue abnormalities and is perhaps not more sensitive than CT in vertebro-basilar TIA. However, in view of the small number of patients these results must be interpreted with caution.