[Visualization of subtle temporal bone structures. Comparison of cone beam CT and MDCT].
OBJECTIVE
The purpose of this study was to compare the visualization of subtle, non-pathological temporal bone structures on cone beam computed tomography (CBCT) and multi-detector computed tomography (MDCT) in vivo.


METHODS
Temporal bone studies of images from 38 patients archived in the picture archiving and communication system (PACS) were analyzed (slice thickness MDCT 0.6 mm and CBCT 0.125 mm) of which 23 were imaged by MDCT and 15 by CBCT using optimized standard protocols. Inclusion criteria were normal radiological findings, absence of previous surgery and anatomical variants. Images were evaluated blind by three trained observers. Using a five-point scale the visualization of ten subtle structures of the temporal bone was analyzed.


RESULTS
Subtle middle ear structures showed a tendency to be more easily distinguishable by CBCT with significantly better visualization of the tendon of the stapedius muscle and the crura of the stapes on CBCT (p = 0.003 and p = 0.033, respectively). In contrast, inner ear components, such as the osseus spiral lamina and the modiolus tended to be better detectable on MDCT, showing significant differences for the osseous spiral lamina (p = 0.001). The interrater reliability was 0.73 (Cohen's kappa coefficient) and intraobserver reliability was 0.89.


CONCLUSIONS
The use of CBCT and MDCT allows equivalent and excellent imaging results if optimized protocols are chosen. With both imaging techniques subtle temporal bone structures could be visualized with a similar degree of definition. In vivo differences do not seem to be as large as suggested in several previous studies.
Universitätsklinik und Poliklinik für HNO-Heilkunde, Kopf- und Halschirurgie, Universitätsklinikum Halle (Saale), Ernst-Grube-Str. 40, 06120, Halle (Saale), Deutschland, katharina.pein@medizin.uni-halle.de.
M K
MK
Pein
S
S
Brandt
S K
SK
Plontke
S
S
Kösling
D000328:Adult; D059925:Anatomic Landmarks / Q000000981:diagnostic imaging*; D054893:Cone-Beam Computed Tomography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods*; D015588:Observer Variation; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013701:Temporal Bone / Q000000981:diagnostic imaging*; D055815:Young Adult