Cerebral blood flow abnormalities induced by transient hypothyroidism after thyroidectomy - Analysis by Tc-99m-HMPAO and SPM96
Cerebral blood flow abnormalities induced by transient hypothyroidism after thyroidectomy - Analysis by Tc-99m-HMPAO and SPM96
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DOI：
10.1007/bf02984562
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发表时间：
2004-09-01
影响因子：
2.6
通讯作者：
Kawai, K
中科院分区：
文献类型：
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作者：
Nagamachi, S;Jinnouchi, S;Kawai, K
本研究旨在探讨甲状腺切除术后短暂性甲状腺功能减退患者局部脑血流量（rCBF）分布的变化。此外，还研究了甲状腺素治疗对rCBF变化的影响。方法：应用99 mTc-HMPAO SPECT对24例甲状腺手术后处于甲减状态的患者进行无创性rCBF测定。在1311治疗前和甲状腺激素（甲状腺素）替代治疗后进行测量。我们使用调整后的rCBF图像（将每个受试者的整体CBF标准化为50 ml/100 g/min，按比例缩放），使用SPM 96将这些数据与年龄匹配的正常对照组（n = 15）进行比较。并与正常对照组比较。此外，还分析了rCBF改变与抑郁症严重程度的关系。最后，甲状腺激素替代对rCBF的影响进行了单独研究，使用刀切试验，其中患者数据与健康志愿者的数据进行了比较。根据试验结果，将所有病例分为三个亚组，即改善组、无变化组和正常组。为证实甲状腺激素替代治疗后rCBF改变的可逆性，对正常对照组和改良组在甲状腺激素替代治疗前后进行了分组对比试验。同样，还进行了原型组和正常对照组之间的组比较试验。结果如下：在甲状腺功能减退的情况下，双侧顶叶的后部和双侧枕叶的部分（包括楔叶）有明显的减少。随着恶化程度加深，这些减少的rCBF区域扩展到双侧前额叶皮质。在个体分析中，24例患者中有16例（66.7%）显示rCBF降低，而8例患者未显示明显的rCBF变化（33.3%，正常组）。甲状腺素替代治疗后，16例患者中有9例（56.3%，改善组）的rCBF改善。在16例患者中的7例（43.7%为无变化组）中，显著的低rCBF面积保持不变。与正常对照组相比，改良组在甲减状态下双侧顶叶和枕叶的rCBF明显降低。甲状腺激素替代治疗后，这些异常的rCBF区域消失。相比之下，在未改变组中，显著的低灌注区域变得局部化但仍然存在。结论：Tc-99 m-HMPAO SPECT和SPM-96分析显示，甲状腺切除术后诱发短暂性甲状腺功能减退症患者顶叶和部分枕叶的rCBF显著降低。这种现象可能有助于理解抑郁状态。部分患者甲状腺激素替代治疗后rCBF恢复。然而，rCBF改善并不总是发生在每个患者在随访期间。短暂性甲状腺功能减退的rCBF的可逆性可能取决于短期内的个体特征。
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. Methods: Noninvasive rCBF measurements using Tc-99m-HMPAO SPECT were performed on 24 post-thyroidectomy patients who were in a hypothyroidic state. The measurements were conducted before 1311 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. Results: 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. Conclusion: Tc-99m-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.