Be careful not to be too quick to say that a patient’s problems are due to canal dehiscence. A study using CT to determine the prevalence of superior and posterior semicircular canal dehiscence in a patient population in Boston calculated the prevalence of superior canal dehiscence; although the result was similar to those from previous investigations (about 9%), this study shows there is a twist-the rate of posterior canal dehiscence may be lower than previously reported.
Explore this issue:September 2008
Previously published studies were in general, large sample size populations but they did not employ sub-millimeter technique. We aren’t aware of any investigations employing sub-millimeter technique in evaluating the posterior semicircular canal, said Rohini Nadgir, MD, Assistant Professor of Radiology at the Boston University School of Medicine, who spoke at a Triological Society session at the Combined Otolaryngology Spring Meeting.
In this retrospective study, researchers reviewed CT scans from patients who had undergone temporal bone CT scans for a variety of clinical indications between July 2005 and March 2007. Scans were done using a sub-millimeter technique to evaluate the integrity of the superior and posterior semicircular canals. The scans were performed on a 64 detector row CT scanner using 0.625-mm slice thickness, in bone plus algorithm without contrast. A review was also done of 0.3-mm interval reconstructions in the coronal and sagittal planes.