Value of sliding-thin-slab maximum intensity projections in imaging of the auditory ossicles

To investigate the image quality with respect to ease of identifying fine structures of auditory ossicles delineated by multislice computed tomography with sliding-thin-slab (STS) maximum intensity projections (MIPs) and multiplanar reformations (MPR).

Fifty patients examined with a standardized protocol on a 16-slice multislice computed tomography were included in the study; the data were reformatted as STS MIP and MPR in 3 planes (axial, coronal, and sagittal) for each subject. Fifteen fine structures of auditory ossicles reformatted by 2 techniques were qualitatively assessed and rated with respect to ease of identifying fine structures of auditory ossicles by 2 blinded readers, and scores of STS MIP reformatted technique assessed by reviewers were compared with those of MPR. kappa Statistics were performed to determine how well the 2 readers agreed on each image; Paired t test was used to determine difference in images quality between MPR and STS MIP.

The kappa values for qualitatively assessing 15 fine anatomical structures revealed high interobserver agreement, independent of the imaging modality (MPR or STS MIP images). Qualitative assessment of 15 fine anatomical structures, the STS MIP reformations were significantly superior to MPR (P < 0.05) in the delineation of 10 of 15 structures; whereas in delineation the remaining 5 of 15 structures, the MPR reformations were superior to STS MIP.

Sliding-thin-slab MIP reformations were significantly superior to MPR with respect to ease of identity of most fine structures of auditory ossicles, but the rest of 5 fine structures (lenticular process of incus, head of stape, anterior crus of stapes, posterior crus of stapes, footplate of stapes) are suitable for visualization using MPR versus MIP.