正常人甲状旁腺超声影像特征的筛查及验证

目的筛选并验证正常人甲状旁腺的主要超声影像特征表现,为临床甲状旁腺疾病的超声诊断及甲状腺外科切除术中正常甲状旁腺的保护提供指导性依据。方法 2008年4月至2012年12月,对600例正常人进行颈部高频超声影像检查,以颈部局部解剖为基础,采用逐一排除法筛选最可能的正常甲状旁腺影像特征。以筛选出的正常甲状旁腺影像特征为基础,比较甲状腺全切除术后甲状旁腺功能低下与否患者甲状旁腺检出率的差异;对比甲状旁腺功能亢进患者的超声影像特征;比较甲状腺切除术中超声监测与否术后甲状旁腺功能低下的发生率,以验证正常甲状旁腺影像的正确性和可靠性。结果正常人甲状旁腺的基本声像图表现为:境界清晰、细腻均匀的中等偏强回声小结节,平均长、宽、厚超声测得值为(6.38±1.46)、(3.76±1.02)、(2.75±1.99)mm;外形多样,以椭圆形居多;质地比邻近的甲状腺实质柔软,弹性超声定量指标应变比平均为0.87±0.18;多数腺体(62.5%)可显示彩色多普勒血流信号;三维重建VOCAL计算平均每枚体积为(0.13±0.06)mL;下甲状旁腺超声显示率及显示质量高于上甲状旁腺。5例甲状腺全切术后血清甲状旁腺激素(PTH)低值者中,有4例(80%)发生正常甲状旁腺声像缺失;而35例甲状腺全切术后血清PTH测值正常者中未见正常甲状旁腺影像缺失。19例原发性甲状旁腺功能亢进和50例继发性甲状旁腺功能亢进患者病变腺体所对应的解剖区域无正常甲状旁腺声像显示。术中未使用超声监测组有6例(20%)术后发生甲状旁腺功能低下,而术中使用超声监测组仅1例(3.3%)发生,组间差异有统计学意义(P<0.01)。2例甲状腺缺如患者在其甲状腺缺如侧高频超声皆显示出2枚正常的甲状旁腺声像。结论成功获得正常人甲状旁腺超声影像,并于临床应用中得到初步验证,为后续研究奠定了基础。

Ultrasonographic features of normal human parathyroids and related validating strategies

Objective To screen for and validate the principal ultrasonographic features of normal human parathyroid glands, so as to provide guidance for diagnostic ultrasound in parathyroid pathologies and protection of normal parathyroid during total thyroidectomy. Methods From Apr. 2008 to Dec. 2012, the neck ultrasonograms focusing on the thyroids and adjacent structures were obtained from 600 healthy subjects. One-by-one identification and exclusion was performed based on anatomical evidences, and the most probable parathyroid images (termed as presumed parathyroid sonogram) of normal human parathyroid were obtained. Based on those presumed parathyroid sonograms, we compared the detection rates of parathyroid in subjects with or without hypoparathyroidism following total thyroidectomy, and we also analyzed the ultrasonic features of patients with hyperparathyroidism. Moreover, we assessed the influence of intraoperative ultrasonography on the occurrence of hypoparathyroidism following total thyroidectomy. The accuracy and reliability of the presumed parathyroid sonogram were discussed. Results It was verified that the normal parathyroid appeared as a small well-circumscribed nodule with fine and homogenous internal hyperechoes. Their configuration varied, with oval shape as the commonest one; the texture was softer than that of adjacent thyroid parenchyma, with the quantitative strain ratio below 1 on elastography. About 62.5% of the normal parathyroids were filled with color Doppler flow signals. The gland was small, with the mean length, width, and thickness being (6.38±1.46), (3.76±1.02), and (2.75±1.99) mm, respectively, and the mean volume was (0.13±0.06) mL by VOCAL method. The inferior glands were much better displayed than the superior ones. As for the patients who had experienced a total thyroidectomy, among five cases complicated with postoperative hypoparathyroidism, 4 (80%) developed the absence of parathyroid on ultrasonography, which was not seen in 35 patients with normal parathyroid function. As for the patients with hyperparathyroidism, normal parathyroid glands were invisible in the area of adenomatous or hyperplastic parathyroids. One patient (3.3%)with intraoperative ultrasonography and six patients (20%) without intraoperative ultrasonography developed postoperative hypoparathyroidism (P<0.01). Two patients with thyroid agenesis showed 2 normal ipsilateral normal parathyroids. Conclusion In the present study we have successfully obtained the ultrasonic features of normal parathyroids using non-invasive research strategies, which have been preliminarily validated in clinical application.