Patterns of abnormality in regional cerebral perfusion and its relation to clinical severity were evaluated with 29 brain injury patients with neurologic symptoms using 99mTc-HMPAO single photon emission tomography(SPECT). The findings were
compared
with computed tomography done within 48 hours of each SPECT study. The initial SPECT study was done within 3 days of injury in 10 cases, between 4 days and 3 weeks in 7 cases and after over 3 weeks in 12 cases. Nineteen patients underwent both
SPECT and
CT after a mean interval of 1 to 2 months.
SPECT could detect abnormal perfusion in patients with nonspecific CT finding and especially, SPECT was significant in chronic stage patients. SPECT detected more lesions than CT in size and number. There were a total of 54 supratentorial SPECT
lesions
in all. Ninity one percent(49/54) of these were of regional hypoperfusion, while 5 lesions(9%) showed focal hypoperfusion. The lesions were most often localized in the frontal and temporal lobes. Cerebellar diaschisis was observed in 55%(16/29)
of
patients. The degree of perfusion abnormality was quantified by product of differential percent activity and a size factor, The degree of perfusion abnormality(SPECT grade) correlates sell with clinical grade(P<0.01), And clinical improvement
correlate
well with follow up SPECT(P<0.005)
Conclusively, SPECT can detect brain perfusion abnormality not found by CT, SPECT may be useful as a complementary study in the evaluation of head injury patient.
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