[Discrepancy between 123I-IMP SPECT and X-ray CT in chronic cerebrovascular disease]

The discrepancy between the low accumulation area (LAA) seen on 123I-IMP SPECT and the low density area (LDA) on X-ray CT was evaluated in 76 cases with chronic cerebrovascular disease. In 19 patients, LAA was larger than LDA beyond the vascular territory. Brain angiogram showed either obstruction or stenosis of the major arteries in as many as 59 percentages of this discrepancy group. In many patients of this group, cortical neurological symptoms were observed. In 37 patients in which the size of LAA was equal to that of LDA, abnormality of the major arteries was observed in only 7 percentages. These results indicated that the discrepancy mainly reflected the infarction due to irreversible ischemic change of perforate artery with the cortical low perfusion caused by the major artery disease. In some patients, the discrepancy was believed to show the remote effect caused by neurological pathway disturbance.