Figure 9d. Absent and hypoplastic cochlear nerves. (a) Axial 3D CISS image shows a severely atretic right IAC with only a sliver of signal intensity (arrow). The cochlear nerve cannot be identified. B = adjacent basal cochlear turn. (b) Adjacent image shows the middle cochlear turn (M). (c) On a maximum-intensity-projection (MIP) image of the left inner ear, the left IAC (I) is narrowed. The cochlea (C) is unremarkable. (d) Sagittal 3D CISS image depicts a hypoplastic left cochlear nerve (C).