Dehiscence of the superior and/or posterior semicircular canal: delineation on T2-weighted axial three-dimensional turbo spin-echo images, maximum intensity projections and volume-rendered images.

The purpose of this study was to compare the ability of T2-weighted three-dimensional turbo spin-echo (TSE) images, maximum intensity projections and three-dimensional volume-rendered images for delineation of semicircular canal dehiscence. In 26 patients with dehiscence of the superior and/or posterior semicircular canal and 26 control patients, TSE images were obtained with two different resolutions and maximum intensity projection (MIP) and 3D volume-rendered images reconstructed. All images were evaluated by two radiologists in consensus regarding the visualization of anatomical structures and dehiscence of the semicircular canals. Computed tomography was used to confirm or exclude dehiscence. Dehiscence of the semicircular canals was delineated on axial MR images and on 3D volume-rendered images, but not on MIP images. The number of false positive cases was reduced from 3 to 0 with an increase in matrix, rendering results similar to those obtained with CT. Dehiscence of the semicircular canals can be assessed on high resolution MR images. Volume-rendered 3D images allow for immediate perception of the location of defects in semicircular canal dehiscence. These images may facilitate understanding of the extent and location of the defects.