"The incidence of superior semicircular canal dehiscence syndrome increases with age."
"MRI is not usually required for the initial diagnosis of superior semicircular canal dehiscence, but there is research showing it may be as good and possibly better than CT. A 2013 study found that MRI had a sensitivity of 100%, specificity of 97%, positive predictive value of 61%, and negative predictive value of 100% compared to CT, making it an excellent "rule out" test 10. However, most surgeons would be reluctant to operate without a CT, as it is far superior in defining the bony anatomy."
"Patients may experience vestibular and visual symptoms. The classic presentation is Tullio phenomenon: vertigo and nystagmus induced by loud noises. Identical clinical manifestations may be provoked by abrupt fluctuations in ambient or intratympanic pressure, for instance, during the execution of the Valsalva manoeuvre, a phenomenon formally recognised as Hennebert's sign. In some, there is a history of longstanding disequilibrium and unsteadiness 1."
"MRI is more often used to follow up patients that have had surgery, allowing assessment of the integrity of the bony covering of the superior semicircular canal. A thin volumetric T2 SPACE is the best sequence."
"Notably, this CT finding has also been described in ~10% of individuals without these clinical features 1; this may be because CT produces a significant false positive rate due to its inherent inability (with technology) to resolve very thin intact soft tissue coverings 11."