I-123 IOFETAMINE SINGLE-PHOTON COMPUTED EMISSION TOMOGRAPHY IN RAPID-CYCLING BIPOLAR DISORDER - A CLINICAL-STUDY

The regional distribution of I-123 iofetamine (IMP) in the brain of 12 patients with rapid cycling bipolar disorder was studied by single-ph oton computed emission tomography imaging, Patients who were either me dication free (n = 4) or on lithium monotherapy (n = 8) were assessed serially in depressed/dysphoric, manic/hypomanic, or euthymic states, In 23 imaging studies, IMP images of the brain were taken on a GE Star cam system 20 min after injection of 3-4 mCi of I-123 labeled IMP. The I-123 IMP distribution in the anterior part of the temporal lobes was asymmetric in both depression/dysphoria and mania/hypomania but not i n euthymia. Images taken sequentially on the same patient showed tempo ral lobe asymmetry in the pathological mood states that diminished or disappeared in the euthymic state, The observed changes most likely re flect an altered cerebral blood flow and changes in high-affinity IMP binding to amine receptors in the temporal lobes, This pilot study sug gests the presence of a state-dependent temporal lobe dysfunction in b ipolar disorder. (C) 1997 Society of Biological Psychiatry