[N-isopropyl-p-[123I]iodoamphetamine early dynamic image with ring-type emission CT in cerebrovascular disease]

N-isopropyl-p-[123I]iodoamphetamine (IMP) SPECT was done in 14 patients with cerebrovascular disease. Immediately after injection of 3 mCi IMP, sequential 2 minutes SPECT images (dynamic images) were obtained for 15 minutes using a circular detector array emission tomographic system (Shimadzu SET-030W). Then standard SPECT images were obtained at 30 minutes (early images) and 5 hours (delayed images) using a rotating scintillation camera ECT system (GCA-601E, Toshiba). Two patients out of 14 studies showed discrepancy of the findings between dynamic images and early images; dynamic images revealed low uptake area though early images showed no defect. Possible mechanism of this phenomenon might be due to so called redistribution phenomenon occurred during obtaining early images. In conclusion, early dynamic images is useful in cases with slightly decreased cerebral blood flow.