Does the washout phenomenon of Tc-99m HM-PAO correlate to the "filling-in" phenomenon of I-123 IMP with brain SPECT?
Using SPECT, the time course of brain uptake was compared between N-isopropyl-p-[I-123]-iodoamphetamine (I-123 IMP) and Tc-99m d,l hexamethyl-propyleneamine oxime (Tc-99m HM-PAO). Of 14 patients with cerebrovascular disease showing areas of the "filling-in phenomenon" (i.e. delayed uptake) with I-123 IMP brain SPECT, 7 exhibited persistent defects with Tc-99m HM-PAO (Group I), and 7 showed early washout after the initial uptake (Group II). The filling-in of I-123 IMP did not always correlate to the washout region of Tc-99m HM-PAO. The temporal changes were also confirmed by semiquantitative analysis. While the filling-in of I-123 IMP was affected by many factors, the washout of Tc-99m HM-PAO was attributed to significant reduction of Tc-99m HM-PAO in the plasma. Delayed imaging of the brain with Tc-99m HM-PAO using SPECT may give a more accurate estimate of regional cerebral blood flow in cerebrovascular disease, because it should be lees effected by cerebral blood volume.
Hayashida
K
K
Department of Diagnostic Radiology, National Cardiovascular Center, Osaka, Japan.
Nishimura
T
T
Imakita
S
S
Uehara
T
T
D000368:Aged; D000662:Amphetamines; D001921:Brain / Q000000981:diagnostic imaging*; D002544:Cerebral Infarction / Q000000981:diagnostic imaging; D002560:Cerebrovascular Circulation / Q000502:physiology; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D020367:Iofetamine; D002546:Ischemic Attack, Transient / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D015609:Organotechnetium Compounds; D010091:Oximes; D019690:Technetium Tc 99m Exametazime; D015899:Tomography, Emission-Computed, Single-Photon
D000662:Amphetamines; D007457:Iodine Radioisotopes; D015609:Organotechnetium Compounds; D010091:Oximes; D019690:Technetium Tc 99m Exametazime; D020367:Iofetamine