Abstract
Objective Tegmen tympani dehiscence in temporal multidetector computed tomography (MDCT) and
superior semicircular canal dehiscence may be seen together. We investigated superior
semicircular canal dehiscence in temporal MDCT and temporal magnetic resonance imaging
(MRI).
Methods In this retrospective study, 127 temporal MRI and MDCT scans of the same patients
were reviewed. In all, 48.8% (n = 62) of cases were male, and 51.2% (n = 65) of cases were female. Superior semicircular canal dehiscence and superior semicircular
canal-temporal lobe distance were evaluated by both MDCT and MRI. Tegmen tympani dehiscence
was evaluated by MDCT.
Results Superior semicircular canal dehiscence was detected in 14 cases (5.5%) by temporal
MDCT and 15 cases (5.9%) by temporal MRI. In 13 cases (5.1%), it was detected by both
MDCT and MRI. In one case (0.4%), it was detected by only temporal MDCT, and in two
cases (0.8%), it was detected by only temporal MRI. Median superior semicircular canal-to-temporal
distance was 0.66 mm in both males and females in temporal MDCT and temporal MRI.
In both temporal MDCT and temporal MRI, as superior semicircular canal-to-temporal
lobe distance increased, the presence of superior semicircular canal dehiscence in
temporal MDCT and temporal MRI decreased. Tegmen tympani dehiscence was detected in
eight cases (6.3%) on the right side and six cases (4.7%) on the left side. The presence
of tegmen tympani dehiscence in temporal MDCT and the presence of superior semicircular
dehiscence in MDCT and MRI increased.
Conclusion Superior semicircular canal dehiscence was detected by both MDCT and MRI. Due to
the accuracy of the MRI method to detect superior semicircular dehiscence, we recommend
using MRI instead of MDCT to diagnose superior semicircular canal dehiscence. Moreover,
there is no radiation exposure from MRI.
Keywords
superior semicircular canal dehiscence - tegmen tympani dehiscence - temporal multidetector
computed tomography - temporal magnetic resonance imaging
