OBJECTIVEThe aim of this study was to find an accurate and feasible measurement technique for the inner ear structures using computed tomography and to check the inter-observer agreement

METHODSSixty patients without abnormal structure of temporal bones confirmed by means of high-resolution computed tomography were included in this study. The multi-planar reformations (MPR) were performed to show the maximum profile of cochlear, and to measure the height and width of cochlear. Areas of bony island encircled by three semicircular canals were measured on the MPR images that could show the whole canal. The data measured by two readers independently was compared to check the inter-observer agreement.

RESULTSThe application of MPR yielded satisfactory anatomic presentation of inner ear for radiologic measurements. There was good inter-observer agreement revealed by the paired t-test and correlation analysis (P>0.05, r>0.9). The height of cochlear (x+/-s) was (4.26+/-0.28) mm while the width of cochlear was (7.03+/-0.39) mm. The areas of bony islands encircled by the anterior, posterior and lateral semicircular canals were (25.49+/-3.84) mm2, (20.07+/-2.93) mm2 and (11.50+/-1.94) mm2, respectively.

CONCLUSIONSMPR can display structures of cochlear and semicircular canals on planes along their central axis. Normative measurements on these MPR images derive excellent repeatability and provide reliable morphologic parameters of inner ear structures.