[Single photon emission computed tomography (SPECT) using 99mTc-hexamethyl propyleneamine oxime in patients with ischemic cerebral diseases: comparative study of N-isopropyl-p-[123I]-iodoamphetamine and 99mTc-DTPA SPECT]

Abstract

In order to confirm the diagnosis and clarify the pathophysiology in the ischemic lesions in brain, 99mTc-PAO SPECT was performed in 42 patients with ischemic cerebral diseases, and the findings on 99mTc-PAO SPECT were compared with those on 123I-IMP or 99mTc-DTPA SPECT, and on X-CT. Furthermore, count ratio of ischemic lesion to normal contralateral region (I/N) was used for the evaluation of the detectability in the lesions on 99mTc-PAO or 123I-IMP SPECT, and less than 0.95 of I/N ratio was defined as the decreased accumulation. The detectability of ischemic lesion in brain with 99mTc-PAO SPECT was 80%, which was superior to that (60%) of LDA on X-CT. Especially, 99mTc-PAO SPECT was useful in cases which were examined early after the onset of the attack. On the other hand, 123I-IMP SPECT showed the best result (88%) in the detectability, and furthermore I/N ratio on 123I-IMP SPECT was lower than that on 99mTc-PAO SPECT. In the delayed phase on 123I-IMP SPECT the redistribution was observed in 30%, while on 99mTc-PAO SPECT it was done in none of them. The accumulation of 99mTc-DTPA in brain was found in 6 of 14 cases (43%), and 2 cases among them also showed the accumulation of 99mTc-PAO in the ischemic lesion. In such cases the destruction of BBB might be considered as the cause of the accumulation of 99mTc-PAO. Thus, 99mTc-PAO SPECT was thought to be useful method in clinical studies of the ischemic cerebral diseases.