[Assessment of cerebral infarction by MRI--particularly fogging effect]

Fogging effect in cerebral infarction was studied by MRI in a 51-year-old male patient. Initial symptoms consisted of mild disturbance of consciousness and left hemiparesis. MRI examination was performed 2, 13 and 22 days after onset and the results were compared with CT findings during the same period. CT on day 2 revealed a wide of infarction in the region of the middle cerebral artery including the basal ganglia. The presence of a fogging effect was seen by CT on day 12 and MRI revealed a high signal intensity in the region of the basal ganglia in T 1 image, a high signal intensity in the peripheral region and a low signal intensity in the center in T 2 image. It was possible to define the lesion as the ordinary infarcted lesion by the subsequent CT and MRI. MRI indicated the infarct lesion was to be a high signal intensity in T1 image and a high signal intensity in the periphery and a low signal intensity in the center in T 2 image. It was concluded that these findings indicated hemorrhage, strongly suggesting that the cause of the fogging effect was hemorrhagic infarction.