Single photon emission computed tomography with 123I-IMP in three cases of the neuroleptic malignant syndrome.

Single photon emission computed tomography (SPECT) perfusion brain scans using 123I-N-isopropyl-p-iodoamphetamine (123I-IMP) were performed in three patients with the neuroleptic malignant syndrome (NMS). In two accumulation was increased in the left basal ganglia and decreased in the right on the early images during the active phase of NMS; this asymmetry was not seen after recovery. In the third patient two examinations were performed during the active phase; on the first, increased accumulation of 123I-IMP in the left basal ganglia was found on the early images, but on the second, increased accumulation of tracer was found in the right basal ganglia on the delayed images. These abnormalities disappeared after improvement of the NMS. These results suggest that a disturbance in the basal ganglia is related to the development of NMS.