Reversible Changes in Brain Glucose Metabolism Following Thyroid Function Normalization in Hyperthyroidism

• Published in: American journal of neuroradiology : AJNR Vol. 32; no. 6; pp. 1034 - 1042
• Main Authors: MIAO, Q, ZHANG, S, GUAN, Y. H, YE, H. Y, ZHANG, Z. Y, ZHANG, Q. Y, XUE, R. D, ZENG, M. F, ZUO, C. T, LI, Y. M
• Format: Journal Article
• Language: English
• Published: Oak Brook, IL American Society of Neuroradiology 01-06-2011
• Subjects: Adult; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Antithyroid Agents - therapeutic use; Biological and medical sciences; Bone marrow, stem cells transplantation. Graft versus host reaction; Brain; Brain - drug effects; Brain - metabolism; Female; Glucose - metabolism; Humans; Hyperthyroidism - drug therapy; Hyperthyroidism - metabolism; Investigative techniques, diagnostic techniques (general aspects); Male; Medical sciences; Methimazole - therapeutic use; Nervous system; Radiodiagnosis. Nmr imagery. Nmr spectrometry; Transfusions. Complications. Transfusion reactions. Cell and gene therapy; Treatment Outcome; Endocrinopathy; Nervous system diseases; Endocrine gland; Radiodiagnosis; Hyperthyroidism; Thyroid diseases; Central nervous system; Thyroid gland; Glucose; Metabolism; Encephalon
• ISSN: 0195-6108; 1936-959X
• DOI: 10.3174/ajnr.a2449

Patients with hyperthyroidism frequently present with regional cerebral metabolic changes, but the consequences of endocrine-induced brain changes after thyroid function normalization are unclear. We hypothesized that the changes of regional cerebral glucose metabolism are related to thyroid hormone levels in patients with hyperthyroid, and some of these changes can be reversed with antithyroid therapy.
Relative regional cerebral glucose metabolism was compared between 10 new-onset untreated patients with hyperthyroidism and 20 healthy control participants by using brain FDG-PET scans. Levels of emotional distress were evaluated by using the SAS and SDS. Patients were treated with methimazole. A follow-up PET scan was performed to assess metabolic changes of the brain when thyroid functions normalized.
Compared with controls, patients exhibited lower activity in the limbic system, frontal lobes, and temporal lobes before antithyroid treatment. There were positive correlations between scores of depression and regional metabolism in the cingulate and paracentral lobule. The severity of depression and anxiety covaried negatively with pretreatment activity in the inferior temporal and inferior parietal gyri respectively. Compared with the hyperthyroid status, patients with normalized thyroid functions showed an increased metabolism in the left parahippocampal, fusiform, and right superior frontal gyri. The decrease in both FT3 and FT4 was associated with increased activity in the left parahippocampal and right superior frontal gyri.
The changes of regional cerebral glucose metabolism are related to thyroid hormone levels in patients with hyperthyroidism, and some cerebral hypometabolism can be improved after antithyroid therapy.