SPECT imaging in psychiatry: introduction and overview.
ABSTRACT Positron emission tomography (PET) and single photon emission computed tomography (SPECT) use advanced computer image construction techniques to illustrate regional cerebral function, metabolism, and chemistry. Although the resolution of PET is higher than that of SPECT, and the technical development of SPECT has lagged behind that of PET, SPECT has recently enjoyed increasingly widespread use, particularly because its costs and technology are within the reach of all clinical nuclear medicine facilities. SPECT imaging agents have greater half-lives than those used with PET, thereby permitting longer and more detailed neurochemistry study than is possible with PET. The research value of both methods has unique potential compared with computed tomography (CT) and magnetic resonance imaging (MRI), which traditionally have provided a static image of the brain's structure or anatomy.
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ABSTRACT: The last decade saw a rapid development of single photon emission computed tomography (SPECT) from a tool to assess cerebral blood flow to the study of specific neurotransmitter systems. Because of the relatively long half-life of SPECT radioisotopes, it is practical to measure the availability of neuroreceptors and transporters in conditions approaching equilibrium. The cost-efficiency of SPECT allowed studies in relatively large samples of patients with various neuropsychiatric disorders. We have applied this approach in studies of dopaminergic, serotonergic, and muscarinergic neurotransmission in patients with dementia, extrapyramidal disorders, schizophrenia, and alcoholism. No simple associations were observed between a single defect in one neurotransmitter system and a certain neuropsychiatric disease. Instead, complex dysfunction of several neurotransmitter systems in multiple, partially connected brain circuits have been implicated. Treatment effects also have been characterized. Microdialysis and neurotransmitter depletion studies showed that most radioligands and endogenous neurotransmitters compete for binding at receptors and transporters. Future research directions include the assessment of endogenous neurotransmitter concentrations measured by depletion studies and of genetic effects on neuroreceptor and transporter expression.Nuclear Medicine and Biology 11/2000; 27(7):677-82. DOI:10.1016/S0969-8051(00)00135-9 · 2.41 Impact Factor
- Developmental Neurorehabilitation 01/2001; 4(2):57-70. DOI:10.1080/13638490110039967 · 1.48 Impact Factor
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ABSTRACT: Data on functional imaging of bipolar disorder (BD) utilizing single photon emission computerized tomography (SPECT) is limited. This study assessed regional cerebral blood flow (rCBF), using (99m)Tc-ECD SPECT, among patients with BD, with mania (N=10) or depression (N=10), compared with 10 patients with unipolar depression and 10 normal controls. Regions of interest were analysed using a semi-automatic brain quantification programme. Compared to controls, patients with mania had significantly reduced perfusion mainly in the left frontal area, also in the left anterior cingulate and parietal cortices; those with bipolar depression had significantly lowered rCBF principally in the anterior temporal regions bilaterally, as well as the left parietal area. Patients with unipolar depression had significantly lowered perfusion than controls in most of the regions examined, chiefly in the anterior temporal and frontal cortices bilaterally; they also had lowered perfusion in the right anterior temporal and frontal areas, as well as the right middle temporal area and the right thalamus, compared to patients with mania. Increased severity of psychotic symptoms was associated with reduced rCBF in patients. These results indicate that altered blood flow in the frontal-subcortical systems characterises patients with BD, as well as those with unipolar depression.The World Journal of Biological Psychiatry 03/2010; 11(2 Pt 2):334-43. DOI:10.3109/15622970802575977 · 4.23 Impact Factor