Subclinical hypothyroidism (SHT) is a common disorder that may represent early thyroid dysfunction and is related to adverse cardiovascular events. However, myocardial injuries induced by SHT are difficult to detect. Our previous study demonstrated that the cardiac magnetic resonance (CMR) myocardial longitudinal relaxation time (T1) mapping technique is a useful tool for assessing diffuse myocardial injuries in overt hypothyroidism patients. This study was designed to detect whether diffuse myocardial injuries were present in SHT by using the T1 mapping technique. We found that SHT participants had significantly increased native T1 values within four segments of the left ventricle (all p < 0.01), especially patients with thyroid-stimulating hormone (TSH) levels ≥10 µIU/mL, compared with those in the controls. In addition, the native T1 values were negatively correlated with free thyroxine (FT4) (r = -0.476, p = 0.003) and were positively correlated with TSH (r = 0.489, p = 0.002). Furthermore, left ventricular diastolic function estimated by the peak filling rate (PFR) was significantly lower in patients with TSH levels ≥10 µIU/mL than that in the controls (p < 0.05). In conclusion, diffuse myocardial injuries were present in SHT, and T1 mapping may be a useful tool for evaluating mild myocardial injuries in SHT at an early stage. Our study is the first to confirm myocardial injuries in SHT patients using T1 mapping.

中文翻译：

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亚临床甲状腺功能减退症中存在弥漫性心肌损伤：使用心肌T1映射定量的临床研究。

亚临床甲状腺功能减退症（SHT）是常见疾病，可能代表早期甲状腺功能障碍，并与不良心血管事件相关。但是，由SHT引起的心肌损伤很难检测。我们先前的研究表明，心脏磁共振（CMR）心肌纵向舒张时间（T1）定位技术是评估明显的甲状腺功能减退症患者弥漫性心肌损伤的有用工具。这项研究旨在通过使用T1定位技术来检测SHT中是否存在弥散性心肌损伤。我们发现，与对照组相比，SHT参与者的左心室四段内的天然T1值显着增加（所有p <0.01），特别是甲状腺刺激激素（TSH）≥10 µIU / mL的患者。此外，天然T1值与游离甲状腺素（FT4）呈负相关（r = -0.476，p = 0.003），与TSH呈正相关（r = 0.489，p = 0.002）。此外，TSH≥10 µIU / mL的患者通过峰值充盈率（PFR）估算的左心室舒张功能显着低于对照组（p <0.05）。总之，SHT中存在弥漫性心肌损伤，T1映射可能是早期评估SHT中轻度心肌损伤的有用工具。我们的研究首次通过T1映射确认SHT患者的心肌损伤。TSH水平≥10µIU / mL的患者通过峰值充盈率（PFR）估算的左心室舒张功能显着低于对照组（p <0.05）。总之，SHT中存在弥漫性心肌损伤，T1映射可能是早期评估SHT中轻度心肌损伤的有用工具。我们的研究首次通过T1映射确认SHT患者的心肌损伤。TSH水平≥10µIU / mL的患者通过峰值充盈率（PFR）估算的左心室舒张功能显着低于对照组（p <0.05）。总之，SHT中存在弥漫性心肌损伤，T1映射可能是早期评估SHT中轻度心肌损伤的有用工具。我们的研究首次通过T1映射确认SHT患者的心肌损伤。