Cerebral infarction within six hours of onset: prediction of completed infarction with technetium-99m-HMPAO SPECT.
Technetium-99m-HMPAO can be used to evaluate abnormal brain perfusion in the hyperacute stage of stroke.


METHODS
We investigated cerebral blood flow using 99mTc-HMPAO SPECT in 31 patients within 6 hr after the onset of cerebral infarction and analyzed the relationship between abnormal perfusion and morphological changes on follow-up CT scans. Patients were classified into an infarct group and a noninfarct group, and the lesions on SPECT images were divided into infarct and peri-infarct regions.


RESULTS
Among a total of 30 infarct regions, three lesions studied at 1.5, 2.5 and 5 hr after the ictus showed local hyperperfusion suggestive of early postischemic hyperemia, while the other 27 lesions demonstrated local hypoperfusion. All of the peri-infarct regions showed moderate hypoperfusion. The noninfarct group consisted of five patients, four of whom showed no perfusion abnormalities. The lesion-to-contralateral radioactivity ratios for the infarct and peri-infarct regions were respectively 0.48 +/- 0.14 and 0.75 +/- 0.10 in the patients with hypoperfusion, while the right-to-left ratio in the noninfarct group was 0.97 +/- 0.10.


CONCLUSIONS
This SPECT study of cerebral blood flow demonstrates that local hyperperfusion occurs in some infarcts even within 6 hr of onset and that infarcted and morphological viable brain can be distinguished by a lesion-to-contralateral radioactivity ratio of 0.6 within this time range.
Shimosegawa
E
E
Department of Radiology and Nuclear Medicine, Research Institute of Brain and Blood Vessels-Akita, Japan.
Hatazawa
J
J
Inugami
A
A
Fujita
H
H
Ogawa
T
T
Aizawa
Y
Y
Kanno
I
I
Okudera
T
T
Uemura
K
K
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000000981:diagnostic imaging*; D002533:Cerebral Angiography; D002544:Cerebral Infarction / Q000000981:diagnostic imaging*; D002560:Cerebrovascular Circulation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015609:Organotechnetium Compounds; D010091:Oximes; D012189:Retrospective Studies; D019690:Technetium Tc 99m Exametazime; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed
D015609:Organotechnetium Compounds; D010091:Oximes; D019690:Technetium Tc 99m Exametazime