Kim Gunho, Rabut Claire, Ling Bill, Shapiro Mikhail, Daraio Chiara
California Institute of Technology.
Res Sq. 2023 May 10:rs.3.rs-2743580. doi: 10.21203/rs.3.rs-2743580/v1.
Functional ultrasound imaging enables sensitive, high-resolution imaging of neural activity in freely behaving animals and human patients. However, the skull acts as an aberrating and absorbing layer for sound waves, leading to most functional ultrasound experiments being conducted after skull removal. In pre-clinical settings, craniotomies are often covered with a polymethylpentene film, which offers limited longitudinal imaging, due to the film's poor conformability, and limited mechanical protection, due to the film's low stiffness. Here, we introduce a skull replacement consisting of a microstructured, conformal acoustic window based on mechanical metamaterials, designed to offer high stiffness-to-density ratio and sonotransparency. We test the acoustic window in vivo, via terminal and survival experiments on small animals. Long-term biocompatibility and lasting signal sensitivity are demonstrated over a long period of time (> 4 months) by conducting ultrasound imaging in mouse models implanted with the metamaterial skull prosthesis.
功能超声成像能够对自由活动的动物和人类患者的神经活动进行灵敏、高分辨率成像。然而，颅骨对声波起到了像差和吸收层的作用，导致大多数功能超声实验是在去除颅骨后进行的。在临床前环境中，开颅手术通常覆盖有聚甲基戊烯薄膜，由于该薄膜的贴合性差，纵向成像受限，且由于其低刚度，机械保护作用有限。在此，我们介绍一种颅骨替代物，它由基于机械超材料的微结构共形声学窗口组成，旨在提供高的刚度与密度比以及超声透明性。我们通过对小动物进行终端和存活实验，在体内测试了该声学窗口。通过在植入超材料颅骨假体的小鼠模型中进行超声成像，在很长一段时间（超过4个月）内证明了其长期生物相容性和持久的信号灵敏度。
