A Tc-99m SPECT study of regional cerebral blood flow in patients with transient global amnesia.
OBJECTIVE
This study aimed to determine whether regional cerebral blood flow (rCBF) is abnormal in patients who have Transient Global Amnesia (TGA).


METHODS
We obtained noninvasive rCBF measurements using Tc-99m-ethyl cysteinate diamer Single Photon Emission Computed Tomography (SPECT) in 7 patients diagnosed with TGA within 4 days of onset of the amnestic episode while the patients were still symptomatic and in 17 age-matched healthy control subjects. We assessed memory functioning using the Hopkins's Verbal Learning Test (HVLT) and Statistical Parametric Mapping to compare rCBF across diagnostic groups.


RESULTS
The patients with TGA were significantly impaired in their performance on the 20-minute delayed recall of the HVLT. They also exhibited significantly decreased rCBF on their SPECT scans in the inferior and middle frontal gyrus bilaterally, with more prominent left-sided reductions in the superior temporal, precentral, and postcentral gyri, as well as increased rCBF primarily in the right hemisphere within the middle temporal, superior temporal, and inferior frontal gyri, cerebellum, and thalamus, compared with the normal control group.


CONCLUSIONS
These findings suggest that lateralized abnormalities in brain functioning are an important component of the pathophysiology of TGA. Lateralized abnormalities may disrupt functions that are relatively specific to the left hemisphere, including receptive language, symbolic representation, and the processing of local features in the environment, while preserving anterograde memory processes. Increased flow to the right hemisphere centered on regions that subserve the functions of expressive language and visuospatial processing, and may represent processes that compensate for flow reductions to the left hemisphere.
Chung
Yong An
YA
Department of Radiology, College of Medicine, The Catholic University of Korea, Seoul, 150-713 South Korea.
Jeong
Jaeseung
J
Yang
Dong Won
DW
Kang
Bong-Joo
BJ
Kim
Sung Hoon
SH
Chung
Soo Kyo
SK
Sohn
Hyung Sun
HS
Peterson
Bradley S
BS
D000368:Aged; D020236:Amnesia, Transient Global / Q000000981:diagnostic imaging* / Q000523:psychology; D001921:Brain / Q000098:blood supply / Q000000981:diagnostic imaging*; D001931:Brain Mapping; D002560:Cerebrovascular Circulation; D003545:Cysteine / Q000031:analogs & derivatives; D005260:Female; D006801:Humans; D008297:Male; D011939:Mental Recall; D008875:Middle Aged; D009483:Neuropsychological Tests; D015609:Organotechnetium Compounds; D015899:Tomography, Emission-Computed, Single-Photon
D015609:Organotechnetium Compounds; C059659:technetium Tc 99m bicisate; D003545:Cysteine