The Transient Disappearance of Cerebral Infarction on T2Weighted MRI

Magnetic resonance imaging (MRI) is as good as, if not better than, X-ray Computed Tomography (CT) for providing useful information about cerebral infarction [1±3]. In particular, newer techniques such as diffusion weighted imaging are very sensitive to the earliest changes of cerebral ischaemia but are not widely available because of hardware limitations [4]. Most centres, therefore, continue to rely on T2-weighted images to recognize the early ischaemic lesion. Most MRI studies emphasize changes that occur acutely; much less is known about the sub-acute changes that occur. Previous observations have established that changes in T2-weighted imaging occur within the ®rst 24 h after the onset of infarction and it has been assumed that these changes persist inde®nitely in permanent infarcts. Here, we report on two patients in whom we found the surprising and intriguing observation that the T2 of the region of infarction returned to normal, or near normal, about 12 days after the onset of stroke but then became abnormal again a few days later.