Reversible hypoperfusion of the cerebral cortex in normal-pressure hydrocephalus on technetium-99m-HMPAO brain SPECT images after shunt operation.

A man with dementia underwent radionuclide cisternography to establish the diagnosis of communicating hydrocephalus. Technetium-99m-HMPAO brain SPECT images showed marked hypoperfusion of both posterior cerebral cortices and three-dimensional displays that demonstrated perfusion defects at both of the posterior parietotemporal regions. A successful ventriculoperitoneal shunt operation was performed. Five and one-half months later, repeat three-dimensional display showed that the perfusion defects had resolved and a repeat brain SPECT image showed marked improvement of the hypoperfusion. This concurred with postoperative clinical improvement. Technetium-99m-HMPAO brain SPECT, which provides objective documentation of clinical recovery after surgery, could be routinely used to evaluate patients with normal-pressure hydrocephalus.