Clinical significance of 123I-iodoamphetamine

For the evaluation of the clinical usefulness of 123I-iodoamphetamine (IMP) with single-photon emission CT (SPECT), sequential studies of dynamic, early static, and delayed static scans were done in 15 cases of brain tumors and 10 cases of cerebral ischemia. On the dynamic scan, IMP accumulation was noted in 6 of the 15 brain tumors, but in none of the cases of cerebral ischemia. A great similarity was noted between the dynamic and early static scans. However, in some of the brain tumors, the IMP accumulation on the dynamic scan was decreased on the early scan. Thus, the blood flow can be more accurately assessed by means of the dynamic scan, although the static scan is superior in spatial resolution. The IMP accumulation in the tumors was more correlated with the angiographic stain than with the positive enhancement on transmission CT. In the cerebral ischemia, the decreased area of the IMP was as wide as, or wider than, that on the transmission CT. On the delayed static scans, a relative increase of the IMP was noted in the white matter of the brain edema and its overlying cortex and in the early stage of cerebral infarction. Thus, it should be mentioned that the IMP accumulation depends not only on the tissue perfusion, but also on the tissue biochemical characteristics, although an IMP study with SPECT is useful for the evaluation of the regional blood flow, especially in the cerebral ischemia. (author)