Cerebral blood flow and related factors in hyperthyroidism patients by SPECT imaging and statistical parametric mapping analysis

Objective: To investigate the cerebral blood flow (CBF) perfusion patterns and related factors in hyperthyroidism patients. Methods: Twenty-five patients with hyperthyroidism and twenty-two healthy controls matched for age, sex, education were enrolled. 99Tcm-ethylene cysteinate dimer (ECD) SPECT CBF perfusion imaging was performed at rest. Statistical parametric mapping 5.0 software (SPM5) was used and a statistical threshold of P<0.05 (corrected) was applied for signifying changes of regional CBF (rCBF). The semiquantitative values of rCBF were extracted automatically by brain search 1.1 software and were correlated with concentrations of serum thyroid hormones (FT3, FT4), thyroid autoimmune antibodies: sensitive thyroid stimulating hormone (sTSH), thyroid peroxidase antibody (TPOAb) and TSH receptor antibody (TRAb) by Pearson analysis, with disease duration by Spearman analysis. Results: rCBF was decreased significantly in limbic system and frontal lobe, including parahippocampal gyrus, uncus (posterior entorhinal cortex, posterior parolfactory cortex, parahippocampal cortex, anterior cingulate, right inferior temporal gyrus), left hypothalamus and caudate nucleus (P<0.05, corrected). rCBF in left lingual gyrus, posterior cingulated was negatively correlated with concentration of FT3 (r=-0.468, -0.417, both P<0.05). rCBF in left lingual gyrus, bilateral inferior temporal gyrus, right superior parietal lobe was negatively correlated with concentration of FT4 (r=-0.4M, -0.418, -0.415, -0.459, all P<0.05), while that in left mammillary body and putamen was positively correlated with concentration of FT4 (r=0.419, 0.412, both P<0.05). rCBF in left insula was negatively correlated with concentration of sTSH, and right auditory associated cortex was positively correlated with concentration of sTSH (r=-0.504, 0.429, both P<0.05). rCBF in left middle temporal gyrus, left angular gyrus was positively correlated with concentration of TRAb while that in right thalamus, right hypothalamus, left anterior nucleus,left ventralis nucleus was negatively correlated with concentration of TRAb (r=0.750, 0.862, -0.691, -0.835, -0.713, -0.759, all P<0.05). rCBF in right anterior cingulate, right cuneus, right rectus gyrus, right superior marginal gyrus was positively correlated with concentration of TPOAb (r=0.696, 0.581, 0.779, 0.683, all P<0.05). rCBF in postcentral gyrus, temporal gyrus, left superior marginal gyrus and auditory associated cortex was positively correlated with disease duration (r=0.502, 0.457, 0.524, 0.440, all P<0.05). Conclusion: Hypoperfusions in limbic system and fontal lobe were found in hyperthyroidism Patients, which might be associated with thyroid function and disesse duration. (authors)