Change of accumulation and filling pattern in evolution of cerebral infarction with I-123 IMP brain SPECT

Twenty-eight patients with cerebral infarction were examined by brain SPECT with I-123 IMP a total of 46 times from Day 2 to Day 84 after the onset of stroke. Depending on the pattern of change in the abnormal accumulation of I-123 IMP between the early and delayed images, the patients were classified into one of five types. The number of patients in each type and the number of days after infarction at which each type occurred were as follows: Type (I), n = 5 and 4 +/- 2 days; Type (II), n = 8 and 12 +/- 4 days; Type (III), n = 17 and 21 +/- 11 days; Type (IV), n = 13 and 38 +/- 18 days; and Type (V), n = 3 and 60 +/- 16 days. In 12 patients, 30 brain SPECT were performed that showed the chronological evolution of infarction in sequence from Types (I) to (IV). Hyperactivity in the early image was seen in Type (I) with a subsequent image defect, while in Type (II) there was persistent hyperactivity. Hypoactivity in the early image was seen in Types (III), (IV), and (V), and the activity in the delayed image gradually decreased as the process of infarction terminated. The early image reflected the distribution of lipophilic I-123 IMP, indicating regional cerebral blood flow, while the delayed image showed the distribution of hydrophilic I-123 IMP metabolites superimposed on that of lipophilic I-123 IMP which had accumulated in the brain at the first extraction. Combining the early and delayed images of I-123 IMP brain SPECT may help to understand the evolution of cerebral infarction.