SPECT IMAGES OF TECHNETIUM-99M-ETHYL CYSTEINATE DIMER IN CEREBROVASCULAR DISEASES - COMPARISON WITH OTHER CEREBRAL PERFUSION TRACERS AND PET

To assess the clinical role of Tc-99m-ethyl cysteinate dimer (ECD) as a cerebral perfusion tracer, 10 patients with unilateral cerebral infa rction were studied. Methods: ECD SPECT images were compared with IMP and/or HMPAO SPECT in nine patients, seven in chronic phases and two i n subacute phases. Five of these patients and one additional patient w ith chronic infarction received PET imaging in order to compare ECD di stribution with quantitative regional cerebral blood flow (rCBF) and o xygen metabolism (rCMRO(2)) images. Results: In patients with chronic cerebral infarction, regression analysis showed excellent correlation between ECD and IMP in the uptake ratio of lesions-to-nonaffected cort ices (r = 0.91). In two cases of subacute infarction, decreased uptake of ECD was observed in the area of ''luxury perfusion,'' which showed elevated or preserved rCBF with diminished rCMRO,. On visual analysis , ECD image contrast was less prominent compared to that of IMP, but c ontrast was better than that of HMPAO. Conclusions: ECD uptake showed a curvilinear relationship against rCBF, suggesting flow-limited uptak e in a high flow range. ECD is a clinically useful cerebral perfusion tracer with distinct characteristics when compared with other availabl e agents.