Fig. 1. Normal cochlea-carotid interval (CCI), measured on coronal CT images as the minimal distance from the basal turn of the cochlea to the carotid canal. Both sides are from a single patient.

A, Right CCI measures 2.1 mm (arrow).

B, Left CCI measures 1.0 mm (arrow).

C, 3D temporal bone reconstruction of a normal CCI shows the normal separation between the cochlea and carotid canal.