technetium-tc-99m-exametazime and Hypothyroidism

The current study is an investigation of alterations in regional cerebral blood flow (rCBF) distribution in patients with transient hypothyroidism after thyroidectomy. In addition, the effects of thyroxine treatment on rCBF changes were studied.. Noninvasive rCBF measurements using 99mTc-HMPAO SPECT were performed on 24 post-thyroidectomy patients who were in a hypothyroidic state. The measurements were conducted before 131I therapy and after thyroid hormone (thyroxine) replacement. We used adjusted rCBF images (normalization of global CBF for each subject to 50 ml/100 g/min with proportional scaling) to compare these data with age-matched normal control groups (n =15) using SPM96. We also compared the absolute rCBF value of hypothyroidic patients with those of normal control groups. In addition, the association between rCBF alteration and the severity of depression was also analyzed. Finally, the effect of thyroid hormone replacement on rCBF was investigated individually using the Jack-knife test, in which patient data were compared with those from healthy volunteers. According to the result of this test, all cases were categorized into three subgroups, namely, improved, unchanged group and normal. To prove the reversibility of rCBF alteration after thyroid hormone replacement, a group comparison test between the normal controls and the improved group was done before and after thyroid hormone replacement. Similarly a group comparison test between the unchanged group and normal controls was also performed.. In the hypothyroidic condition, there was a significant decrease in the posterior part of the bilateral parietal lobes and in part of the bilateral occipital lobes, including the cuneus. These decreased rCBF areas extended to the bilateral prefrontal cortices as deterioration became more profound. On individual analysis, 16 of 24 patients (66.7%) demonstrated rCBF reduction, while 8 patient did not show significant rCBF change (33.3%, the normal group). After thyroxine replacement, improvement of rCBF was noted in nine of 16 patients (56.3%, the improved group). In seven of 16 patients (43.7% the unchanged group), the significant low rCBF area remained unchanged. Compared with the normal controls, the improved group showed significantly decreased rCBF of the bilateral parietal lobe and the occipital lobe in the hypothyroic condition. After thyroid hormone replacement, these abnormal rCBF areas disappeared. In contrast, in the unchanged group, the significant hypoperfusion area became localized but remained.. 99mTc-HMPAO SPECT and SPM96 analysis demonstrated a significant rCBF decrease in the parietal lobe and part of the occipital lobe in patients with induced transient hypothyroidism after thyroidectomy. This phenomenon might contribute to understanding of the depressive state. Recovery of rCBF after thyroid hormone replacement was confirmed in some patients. However, rCBF improvement did not always occur in every patient during the follow up period. The reversibility of rCBF in transient hypothyroidism may be dependent on individual characteristics during a short-term period.

Topics: Adult; Aged; Brain; Cerebrovascular Circulation; Depression; Dose-Response Relationship, Drug; Female; Humans; Hypothyroidism; Male; Middle Aged; Psychiatric Status Rating Scales; Radionuclide Imaging; Radiopharmaceuticals; Severity of Illness Index; Technetium Tc 99m Exametazime; Thyroid Neoplasms; Thyroidectomy; Thyroxine

Hypothyroidism and major depressive disorder (MDD) share neuropsychiatric features. Cerebral perfusion deficits are found in both disorders. We compared regional cerebral blood flow (rCBF) in hypothyroidism and MDD to determine if clinical similarities are mediated by common neurocircuitry. Ten hypothyroid and 10 depressed patients underwent 99mTc-HMPAO-SPECT and clinical evaluation before and after response to respective treatments. Ten healthy controls underwent a similar, single, evaluation. Before treatment, rCBF in hypothyroid and depressed patients was lower than in controls, in posterior and anterior aspects of the brain respectively. rCBF in hypothyroidism was lower than in MDD in right posterior cingulate and parieto/occipital regions, and higher in frontal, prefrontal and sub-genual regions. Reduced rCBF in pre- and post-central gyri was found in both groups. Following treatment, rCBF in depressed patients increased and normalized, but remained unchanged in hypothyroidism. Affective symptoms in hypothyroidism may be mediated by neurocircuitry different from that of major depression.

Topics: Adult; Aged; Antidepressive Agents; Brain; Case-Control Studies; Cerebrovascular Circulation; Cohort Studies; Depressive Disorder, Major; Female; Humans; Hypothyroidism; Male; Middle Aged; Pilot Projects; Radiopharmaceuticals; Severity of Illness Index; Technetium Tc 99m Exametazime; Thyroxine; Tomography, Emission-Computed, Single-Photon; Treatment Outcome

The aim of this study was to assess regional cerebral blood flow (rCBF) using detailed semiquantitative analysis of Technetium-99m hexamethylpropyleneamine (HMPAO) brain single-photon emission computerized tomography (SPECT) in patients with hypothyroidism due to autoimmune thyroiditis.. Twenty patients (mean age: 42+/-9 yr) and 12 control subjects (mean age: 35.4+/-8.5 yr) were included in this study. The corticocerebellar rCBF ratios were obtained from 52 cerebral areas on 6 transaxial slices. By using control group rCBF ratios, lower reference values (RLV) (average ratio -2 SD) were calculated and the regions below RLV having an rCBF ratio were considered as abnormal decrease (hypoperfused) areas.. Significant reduced rCBF rates were measured for 15 (29%) cortical regions for the patient group. The areas in which significant reduced rCBF were demonstrated in the patient group were as follows: a) in the right hemisphere: superior frontal (slice 1 and 2), inferior frontal (slice 1), anterior temporal (slice 1 and 2), precentral gyrus (slice 1 and 2), postcentral gyrus (slice 1 and 2), and parietal cortex; b) in the left hemisphere: superior frontal (slice 1 and 2), inferior frontal (slice 1), caudate nucleus, and parietal cortex. The hypoperfusion was calculated in 154 (14%, 94 right and 60 left) cortical regions out of 1040 regions in the patient group.. These findings indicate that the alteration of rCBF in patients with hypothyroidism due to Hashimoto's thyroiditis before T4 therapy can be demonstrated with brain SPECT. Additionally, the degree of rCBF abnormalities could be determined with brain SPECT in patients with hypothyroidism due to Hashimoto's thyroiditis with or without neurologic or psychiatric symptoms.

Topics: Adult; Cerebrovascular Circulation; Cerebrum; Female; Hashimoto Disease; Humans; Hypothyroidism; Male; Middle Aged; Radiopharmaceuticals; Regional Blood Flow; Technetium Tc 99m Exametazime; Thyroid Gland; Thyroxine; Tomography, Emission-Computed, Single-Photon

In recent years, it has been possible for patients with Down syndrome to live longer with advanced medical treatment and social support. As a result, the problems of these patients, such as thyroid diseases, leukemia, and Alzheimer disease, would be encountered more frequently. In this study, we aimed to perform the brain perfusion of children with Down syndrome by technetium 99m hexamethylpropylene amine oxime (99mTc-HMPAO) single-photon emission computed tomography (SPECT) and to determine the relationship between brain perfusion and epilepsy, thyroid function tests, congenital heart disease, and level of mental and motor development. Thirty patients with Down syndrome, aged between 1 and 15 years, were included in our study. Demographic data, the existence of epilepsy and congenital heart defects, the level of mental and motor development, serum levels of thyroid hormones, and autoantibodies were determined. All patients underwent computed tomography (CT) and/or magnetic resonance imaging (MRI). Cerebral SPECT was performed in all cases to evaluate the brain perfusion pattern. According to the visual evaluation of cerebral SPECT results, hypoperfusion was detected in 11 cases (37%). Patients with cerebral hypoperfusion (group 1) and patients with normal cerebral perfusion (group 2) were compared. There was no difference between group 1 and group 2 in terms of demographic data, congenital heart defects, IQ levels, thyroid hormones, and autoantibodies, but the incidence of epilepsy was significantly higher in group 1 (P<.001). When motor and mental development levels were compared, it was found that cases in group 1 were significantly more retarded in personal-social and fine motor skills (P<.05). The present study showed that cerebral hypoperfusion in children with Down syndrome is mostly related to epilepsy and the other coexisting conditions, congenital heart disease and hypothyroidism. Patients with cerebral hypoperfusion also have more retarded developmental levels, especially in personal-social and fine motor skills.

Topics: Adolescent; Cerebrovascular Circulation; Child; Child Development; Child, Preschool; Down Syndrome; Epilepsy; Female; Heart Defects, Congenital; Humans; Hypothyroidism; Infant; Intelligence; Male; Motor Skills; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

A 69-year-old man had hypothyroid dementia as a result of I-131 therapy and an overdose of methimazole. Tc-99m HMPAO SPECT revealed diffuse cerebral hypoperfusion. The findings of brain SPECT normalized with the disappearance of symptoms and a return to the euthyroid state. There was a 25% or 26% reduction of the mean cerebral blood flow during dementia. This may be the first report in which SPECT brain imaging revealed reversible hypoperfusion associated with reversible hypothyroid dementia.

Topics: Aged; Antithyroid Agents; Brain; Cerebrovascular Circulation; Dementia; Graves Disease; Humans; Hypothyroidism; Iodine Radioisotopes; Male; Methimazole; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon