Detection of porencephaly by cerebral dynamic scanning.

Routine cerebral dynamic scanning in two patients revealed unilateral focal areas of decreased radionuclide activity between the anterior and middle cerebral arteries; the subsequent brain scans were normal. Both patients were shown to have porencephaly by isotope cisternography and computed tomography (CT) scans. When a focal avascular area is noted on cerebral dynamic scanning in the presence of normal static images, the possibility of a porencephalic cyst should be considered.