彈性造影學已被廣泛用於診斷許多疾病，例如乳腺癌和肝硬化等。現有的商業用超音波彈性造影系統使用低頻率（<15 MHz）超音波探頭來檢測剪切波速度並將其轉換為彈性。低頻率超音波探頭用於評估淺薄組織時無法提供高分辨率影像，且大多數過去的臨床研究未能考慮到淺薄組織中的色散效應，這可能導致在評估剪切波速時出現偏差或誤差，使得計算出的彈性也會產生偏差。此外，皮膚也被認定為各向異性材料，意即在不同方向上所評估的結果會有所不同。
本研究中，我們使用外部振動器在組織內產生剪切波，利用高頻超音波探頭來檢測剪切波的傳播，並改變震動器及超音波探頭的角度以測量在不同方向上的皮膚黏彈性。我們進行了仿體實驗來驗證該技術的系統設置和算法，在0至30% 的油性仿體中，彈性分別為8.16 、7.00 、9.23 及 10.87 kPa；黏性分別為 0.99、2.30、3.27 及4.40 Pa*S。結果顯示，該技術是可靠的，估計結果比剪切波模型估計的結果更準確。再來我們將此技術應用於兩位受試者並測量其健康皮膚粘彈性之各向異性。結果表明，該技術能夠區分正常皮膚各方向上的粘彈性。

Elastography has been widely used for diagnosing various diseases, such as breast cancer and liver cirrhosis. Existing commercial ultrasound elastography systems use low-frequency transducers (<15 MHz) to detect shear wave velocity and convert it into elasticity. However, the low-frequency transducers were unable to provide high-resolution images for thin-layer tissues. Moreover, most previous clinical studies did not consider the dispersion effect in thin-layer tissues, which could lead to biases or errors in shear wave estimation, consequently affecting the calculated elasticity. In additional, the skin has been recognized as an anisotropic material, which means that the evaluated results could vary in different directions.
In this study, we generated shear waves within the tissues using an external vibrator. A high-frequency transducer was used to detect the propagation of shear waves. In each experiment, we adjusted the angles of the vibrator and transducer to measure the skin's viscoelastic properties in different directions. We conducted phantom experiments to verify the system settings and algorithms of this technology. In 0 to 30% oily phantoms, the elasticities were 8.16, 7.00, 9.23 and 10.87 kPa; the viscosities were 0.99, 2.30, 3.27 and 4.40 Pa*S. The technique was shown to be reliable, and the estimates were more accurate than those estimated by the shear wave model. The results showed that this technique is reliable, and the estimated results were more accurate than those estimated by the shear wave model. Subsequently, we applied this technique to several subjects to measure the anisotropy of skin's viscoelastic properties. The results demonstrated that this technique could differentiate the viscoelastic properties of normal skin in different directions.

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