SPECT Assessment of Cerebral Perfusion in Head Injury

ABSTRACT

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 3days of injury in 10 cases, between 4days 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 hyperperfusion. 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 percents activity and size factor. The degree of perfusion abnormality(SPECT grade) correlates well with clinical grade(P<0.01). And clinical improvement correlate well with follow up SPECT(P<0.05). Conclusively, SPECT can defect brain perfusion abnormality not found by CT. SPECT may be useful as a complementary study in the evaluation of head injury patient.