The repair of peripheral nerve injuries with autologous nerve remains the gold standard (Wang et al., 2005; Yao et al., 2010; Deal et al., 2012; Kriebel et al., 2014; Liu et al., 2014; Tamaki et al., 2014; Yu et al., 2014; Zhu and Lou, 2014). With advances in tissue engineering and biomaterials, tissue-engineered nerve conduits with various biomaterials and structures, such as collagen and chitosan nerve conduits, have already been used in the clinic as alternatives to autologous nerve in the repair of peripheral nerve injury (Wang et al., 2012; Sví?enská et al., 2013; Eppenberger et al., 2014; Gu et al., 2014; Koudehi et al., 2014; Moya-Díaz et al., 2014; Novajra et al., 2014; Okamoto et al., 2014; Shea et al., 2014; Singh et al., 2014; Tamaki et al., 2014; Yu et al., 2014). Therefore, new simple and effective methods are needed to better evaluate the outcomes of repair using nerve conduits in vivo. Ultrasound is a common noninvasive clinical detection modality that has been used in many fields. However, ultrasound has only rarely been used to observe implanted nerve conduits in vivo. Haug et al. (2013) tried to displace the collagen nerve conduit for repairing the digital nerve under ultrasound. Here, we report the first use of ultrasound to noninvasively observe the changes in chitosan nerve conduits implanted in rats over time.