How to interpret differing cerebral blood flow patterns estimated with 99Tcm-HMPAO and 99Tcm-ECD SPET in a healthy population.
Two radiopharmaceuticals, 99Tcm-hexamethyl propylene amine oxime (99Tcm-HMPAO) and 99Tcm-ethyl cysteinate dimer (99Tcm-ECD), are currently used to determine cerebral blood flow. 99Tcm-ECD is, by virtue of its greater stability, superseding 99Tcm-HMPAO for routine examinations. Since the clinical assessment of 99Tcm-ECD images is usually based on experience with 99Tcm-HMPAO, we used both radiopharmaceuticals to compare regional cerebral blood flow in the same individuals. Eleven healthy subjects aged 67.1 +/- 6.3 years (mean +/- S.D.) underwent 99Tcm-ECD followed by 99Tcm-HMPAO single photon emission tomography. Cerebral blood flow was quantified in cortical and central regions of interest (basal ganglia, ventricles, white matter) in relation to cerebellar uptake. The intra-subject comparison of cerebral blood flow in the cortical areas revealed higher levels of perfusion in the posterior parietal, parieto-occipital and temporo-occipital areas using 99Tcm-ECD. In contrast to the cortical areas, cerebral blood flow in the central areas was greater using 99Tcm-HMPAO, especially in the centrum semiovale, basal ganglia, frontal white matter and frontal horns. This difference in cerebral blood flow when imaging healthy individuals with 99Tcm-ECD and 99Tcm-HMPAO should be taken into account in clinical practice when changing from one radiopharmaceutical to the other.
Siennicki-Lantz
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Department of Community Medicine, Malmö University Hospital, Lund University, Sweden.
Lilja
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Elmståhl
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D000368:Aged; D001921:Brain / Q000000981:diagnostic imaging; D002560:Cerebrovascular Circulation / Q000502:physiology*; D003545:Cysteine / Q000031:analogs & derivatives*; D005260:Female; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000000981:diagnostic imaging; D008875:Middle Aged; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D012016:Reference Values; D019690:Technetium Tc 99m Exametazime; D014055:Tomography, Emission-Computed; D014980:Xenon Radioisotopes
D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D014980:Xenon Radioisotopes; D019690:Technetium Tc 99m Exametazime; C059659:technetium Tc 99m bicisate; D003545:Cysteine