A pulsed terahertz (THz) imaging system and millimeter-wave reflectometer were used to acquire images and point measurements, respectively, of five rabbit cornea in vivo. These imaging results are the first ever produced of in vivo cornea. A modified version of a standard protocol using a gentle stream of air and a Mylar window was employed to slightly dehydrate healthy cornea. The sensor data and companion central corneal thickness (CCT) measurements were acquired every 10-15 min over the course of two hours using ultrasound pachymmetry.. Statistically significant positive correlations were established between CCT measurements and millimeter wave reflectivity. Local shifts in reflectivity contrast were observed in the THz imagery; however, the THz reflectivity did not display a significant correlation with thickness in the region probed by the 100 GHz and CCT measurements. This is explained in part by a thickness sensitivity at least 10 × higher in the mm-wave than the THz systems. Stratified media and effective media modeling suggest that the protocol perturbed the thickness and not the corneal tissue water content (CTWC). To further explore possible etalon effects, an additional rabbit was euthanized and millimeter wave measurements were obtained during death induced edema. These observations represent the first time that the uncoupled sensing of CTWC and CCT have been achieved in vivo.

中文翻译：

---

角膜组织含水量的太赫兹和毫米波传感：体内传感和成像结果

使用脉冲太赫兹 (THz) 成像系统和毫米波反射计分别采集 5 只兔角膜的体内图像和点测量。这些成像结果是有史以来首次产生的体内角膜。使用温和的空气流和聚酯薄膜窗口的标准协议的修改版本被用来使健康的角膜稍微脱水。传感器数据和伴随中央角膜厚度 (CCT) 测量值在两小时内使用超声测厚仪每 10-15 分钟采集一次。在 CCT 测量值和毫米波反射率之间建立了统计学上显着的正相关。在太赫兹图像中观察到反射率对比度的局部变化；然而，太赫兹反射率与 100 GHz 和 CCT 测量探测区域的厚度没有显着相关性。部分原因是毫米波的厚度灵敏度比太赫兹系统高至少 10 倍。分层介质和有效的介质建模表明该协议扰乱了厚度而不是角膜组织含水量 (CTWC)。为了进一步探索可能的标准具效应，另外一只兔子被安乐死，并在死亡引起的水肿期间获得了毫米波测量值。这些观察结果代表了首次在体内实现了 CTWC 和 CCT 的非耦合传感。分层介质和有效的介质建模表明该协议扰乱了厚度而不是角膜组织含水量 (CTWC)。为了进一步探索可能的标准具效应，另外一只兔子被安乐死，并在死亡引起的水肿期间获得了毫米波测量值。这些观察结果代表了首次在体内实现了 CTWC 和 CCT 的非耦合传感。分层介质和有效的介质建模表明该协议扰乱了厚度而不是角膜组织含水量 (CTWC)。为了进一步探索可能的标准具效应，另外一只兔子被安乐死，并在死亡引起的水肿期间获得了毫米波测量值。这些观察结果代表了首次在体内实现了 CTWC 和 CCT 的非耦合传感。