Purpose

The pyramidal lobe (PL) is an ancillary lobe of the thyroid gland that can be affected by the same pathologies as the rest of the gland. We aimed to assess the diagnostic performance of high-resolution sonography in the detection of the PL with verification by dissection and histological examination.

Methods

In a prospective, cross-sectional mono-center study, 50 fresh, non-embalmed cadavers were included. Blinded ultrasound examination was performed to detect the PL by two investigators of different experience levels. If the PL was detected with ultrasound, dissection was performed to expose the PL and obtain a tissue sample. When no PL was detected with ultrasound, a tissue block of the anterior cervical region was excised. An endocrine pathologist microscopically examined all tissue samples and tissue blocks for the presence of thyroid parenchyma.

Results

The prevalence of the PL was 80% [40/50; 95% CI (68.9%; 91.1%)]. Diagnostic performance for both examiners was: sensitivity (85.0%; 42.5%), specificity (50.0%; 60.0%), positive predictive value (87.2%; 81.0%), negative predictive value (45.5%; 21.0%) and accuracy (78.0%; 46.0%). Regression analysis demonstrated that neither thyroid parenchyma echogenicity, thyroid gland volume, age nor body size proved to be covariates in the accurate detection of a PL (p > .05).

Conclusion

We report that high-resolution ultrasound is an adequate examination modality to detect the PL. Our findings indicate a higher prevalence than previously reported. Therefore, the PL may be regarded as a regular part of the thyroid gland. We also advocate a dedicated assessment of the PL in routine thyroid ultrasound.

中文翻译：

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超声检测甲状腺锥体叶

目的

锥体叶 (PL) 是甲状腺的附属叶，可能会受到与腺体其他部位相同的病理影响。我们的目的是通过解剖和组织学检查来评估高分辨率超声检查在 PL 检测中的诊断性能。

方法

在一项前瞻性、横断面单中心研究中，包括 50 具新鲜、未经防腐处理的尸体。由两名不同经验水平的研究人员进行了盲法超声检查以检测 PL。如果用超声波检测到 PL，则进行解剖以暴露 PL 并获得组织样本。当超声未检测到 PL 时，切除了颈前区的组织块。内分泌病理学家用显微镜检查所有组织样本和组织块是否存在甲状腺实质。

结果

PL 的患病率为 80% [40/50; 95% CI (68.9%; 91.1%)]。两位检查者的诊断性能为：敏感性（85.0%；42.5%）、特异性（50.0%；60.0%）、阳性预测值（87.2%；81.0%）、阴性预测值（45.5%；21.0%）和准确性（78.0 %；46.0%）。回归分析表明，甲状腺实质回声、甲状腺体积、年龄和体型都不是准确检测 PL 的协变量 ( p  > .05)。

结论

我们报告高分辨率超声是检测 PL 的适当检查方式。我们的研究结果表明患病率高于先前报道的。因此，PL可以被视为甲状腺的一个规则部分。我们还提倡在常规甲状腺超声检查中对 PL 进行专门评估。