Sequential change of heterogeneous cerebral blood blow patterns after diffuse brain ischemia

In order to provide an insight into the basic nature of ischemic brain injury, we sequentially studied cerebral blood flow with [99mTc]hexamethylpropyleneamine oxime single photon emission computed tomography (CBF imaging) in a patient with diffuse brain ischemia due to prolonged cardiac arrest. On the 10th postarrest day, concentrated blood flow over superior-medial portion of the occipital lobe was demonstrated. On the 18th postarrest day, the same region became high density on a CT scan, while the concentrated flow on the CBF imaging had diminished. Thus, an abnormal cerebral blood flow (CBF) pattern preceded the density change on CT scan. On the 23rd postarrest day, remarkably concentrated flow over the brainstem was demonstrated. This might have illustrated the reduced metabolic demand of the damaged tissue over the cerebral and cerebellar hemispheres with relative preservation of brainstem perfusion. In patients with diffuse brain ischemia, a CBF imaging may be a useful tool for clarifying pathological process and prognosis.