Hypoxic brain injury is one of the major causes of cerebral palsy. Therefore, this study was performed to evaluate cerebral perfusion impairments in these patients using 99mTc-ECD brain SPECT. METHODS Fifty-one patients (31 boys, 20 girls; age range 6 mo to 6 yr, 11 mo) with clinical manifestations of cerebral palsy underwent brain SPECT after intravenous injection of 99mTc-ECD. The clinical subtypes of cerebral palsy were spastic diplegia (n = 35), spastic quadriplegia (n = 11), spastic hemiparesis (n = 2), choreoathetoid (n = 2) and mixed (n = 1). Transaxial, coronal and sagittal images obtained with a brain-dedicated annular crystal gamma camera were qualitatively analyzed and compared with the findings of magnetic resonance imaging (MRI). RESULTS In SPECT, thalamic hypoperfusion was seen in all patients except one (98%), followed by hypoperfusion in the temporal lobe (52.9%, n = 27), basal ganglia (41.2%, n = 21), cerebellum (39.2%, n = 20) and extratemporal cortices (21.6%, n = 11). However, MR imaging demonstrated thalamic abnormality in seven (13.7%), basal ganglia in two (3.9%), extratemporal cortical defect in five (9.8%) and cerebellar atrophy in one (1.9%). Instead, white matter changes such as periventricular leukomalacia or ischemia (56.9%, n = 25) and thinning of corpus callosum (49%, n = 25) were the major findings. CONCLUSIONS Brain SPECT is useful in the diagnosis of cerebral palsy and is more sensitive in the detection of cortical, subcortical nuclei and cerebellar abnormalities. MRI is superior in the detection of white matter changes.