Department of Internal Medicine 1, J.W. Goethe-University Hospital, Frankfurt, Germany.
Ultrasonics. 2012 Jan;52(1):69-74. doi: 10.1016/j.ultras.2011.06.012. Epub 2011 Jul 7.
Real-time tissue elastography, a qualitative elastography method, has shown promising results in the diagnostic work up of thyroid nodules. However, to our knowledge no study has evaluated a quantitative elastography method in the thyroid gland. The present study is a feasibility study evaluating Acoustic Radiation Force Impulse-Imaging, a novel quantitative elastography method in the thyroid gland.
ARFI-imaging involves the mechanical excitation of tissue using short-duration acoustic pulses to generate localized displacements in tissue. The displacements induce a lateral shear-wave propagation which is tracked using multiple laterally positioned ultrasound "tracking" beams. Inclusion criteria were: thyroid nodules ≥1cm, non-functioning or hypo-functioning on radionuclide scanning, and cytological/histological assessment of thyroid nodule as reference method. All patients received conventional ultrasound, and examination of the thyroid gland including Power Doppler Ultrasound using a 9MHz linear transducer, in addition real-time elastography (RTE) was performed at 9MHz frequency and ARFI-imaging was performed at 4MHz using Siemens (ACUSON S2000) B-mode-ARFI combination transducer.
Sixty nodules in 55 patients were analyzed. Three nodules were papillary carcinoma. The stiffer the tissue the faster the shear wave propagates. The results obtained indicated that the shear wave velocity in thyroid lobes ranged between 0.5 and 4.9m/s. The median velocity of ARFI-imaging in the healthy nodule-free thyroid gland, as well as in benign and malignant thyroid nodules was 1.98m/s (range: 1.20-3.63m/s), 2.02m/s (range: 0.92-3.97m/s), and 4.30m/s (range: 2.40-4.50m/s), respectively. While no significant difference in median velocity was found between healthy thyroid tissue and benign thyroid nodules, a significant difference was found between malignant thyroid nodules on the one hand and healthy thyroid tissue (p=0.018) or benign thyroid nodules (p=0.014) on the other hand. Specificity of ARFI-imaging for the differentiation of benign and malignant thyroid nodules was comparable with RTE (91-95%).
ARFI can be performed in the thyroid tissue with reliable results.
实时组织弹性成像（一种定性弹性成像方法）在甲状腺结节的诊断中已显示出良好的效果。然而，据我们所知，目前尚无研究评估甲状腺的定量弹性成像方法。本研究是一项评估声辐射力脉冲成像（一种新的甲状腺定量弹性成像方法）的可行性研究。
声辐射力脉冲成像（ARFI）通过使用短持续时间的声脉冲机械激发组织，在组织中产生局部位移。这些位移会引起横向剪切波传播，使用多个横向定位的超声“跟踪”波束跟踪该传播。纳入标准为：结节大小≥1cm、核素扫描无功能或低功能、甲状腺结节的细胞学/组织学评估为参考方法。所有患者均接受常规超声检查，并使用 9MHz 线性探头进行甲状腺检查，包括能量多普勒超声，此外还在 9MHz 频率下进行实时弹性成像（RTE），在 4MHz 频率下使用西门子（ACUSON S2000）B 模式-ARFI 组合探头进行 ARFI-成像。
对 55 例患者的 60 个结节进行了分析。其中 3 个结节为甲状腺乳头状癌。组织越硬，剪切波传播速度越快。结果表明，甲状腺叶中的剪切波速度范围在 0.5 至 4.9m/s 之间。无功能性甲状腺结节、良性和恶性甲状腺结节中健康甲状腺组织的 ARFI 成像剪切波速度中位数分别为 1.98m/s（范围：1.20-3.63m/s）、2.02m/s（范围：0.92-3.97m/s）和 4.30m/s（范围：2.40-4.50m/s）。虽然健康甲状腺组织与良性甲状腺结节之间的中位速度无显著差异，但恶性甲状腺结节与健康甲状腺组织（p=0.018）或良性甲状腺结节（p=0.014）之间的差异有统计学意义。ARFI 成像对良恶性甲状腺结节的鉴别诊断特异性与 RTE 相当（91-95%）。
ARFI 可在甲状腺组织中可靠地进行。
