[Difference in the distribution of 123I-IMP and 99mTc-HMPAO in the striatum--comparison with 15O-PET]

Brain perfusion SPECT studies of 123I-IMP and 99mTc-HMPAO were performed in 10 patients with various brain disorders and the difference in the distribution of 123I-IMP and 99mTc-HMPAO in the cortices and striatum was compared with the cerebral blood flow by 15O-PET method. The ratios of the radioactivity in 14 ROIs of the cortices, striatum and cerebellum to that of the reference region or the right frontal cortex were compared among the 3 studies. The coefficient variance between 123I-IMP and PET was 0.71 and that between 99mTc-HMPAO and PET was 0.74 in the regions excluding the striatum. The striatal activity ratio in 123I-IMP was slightly less than those in 99mTc-HMPAO and PET which were close to each other. The visual activity in the striatum in 123I-IMP was also slightly less than those in 99mTc-HMPAO and PET. All the striatal lesions of decreased perfusion diagnosed by PET were observed in 123I-IMP, however 2 lesions were missed in 99mTc-HMPAO. This seems to be relevant to the difference in the distribution of 123I-IMP and 99mTc-HMPAO.