Serial perfusion brain tomographic scans detect reversible focal ischaemia in Rasmussen's encephalitis

A 39-year-old man with advanced adult-onset Rasmussen's encephalitis was treated with prednisolone and long-term, high-dose, human intravenous immunoglobulin. A pretreatment, semiquantitative interictal brain perfusion single photon emission computed tomography (SPECT) scan using (99)Tc(m) HMPAO (hexamethylene propylene amine oxime) showed hypoperfusion in the clinically affected right frontal, parietal and temporal lobes and contralateral perfusion defects. A second scan 8 months later revealed significant improvements (more than two standard deviations) in perfusion of the right frontal and temporal lobes despite serial magnetic resonance imaging evidence of permanent brain damage. This was associated with useful recovery of the patient's physical and cognitive function. We conclude that serial perfusion brain SPECT scanning is a useful method to demonstrate improvement in patients with Rasmussen's encephalitis in response to therapy.