Technetium-99m HM-PAO single photon emission computed tomography imaging in transient global amnesia
P. Laloux, C. Brichant, F. Cauwe and P. Decoster
Department of Neurology, Mont-Godinne Hospital, University of Louvain, Yvoir, Belgium.
Five right-handed patients with pure transient global amnesia were
evaluated with technetium-99m hexamethylpropyleneamine oxime single photon
emission computed tomography after the amnesic attack. Independent of the
interval between the procedure and the amnesic episode, single photon
emission computed tomography demonstrated a decreased cerebral blood flow
in the left temporal lobe in one patient and in the left parietotemporal
region in three patients, with a more marked reduction in the temporal
lobe. The remaining three patients were normal. A control single photon
emission computed tomographic study was carried out in one patient 3 months
after the amnesic attack and showed a left-sided persistent temporal
hypoperfusion. These findings suggest that in some patients, transient
global amnesia can be due to a vascular mechanism requiring strong
investigations for vascular risk factors and appropriate treatment. During
a follow-up period of 12 to 32 months, none of the patients with regional
hypoperfusion suffered cerebrovascular events, suggesting that single
photon emission computed tomography has no predictive value for further
stroke.
