Cone beam CT has been shown to be superior to multidetector CT for detecting superior semicircular canal dehiscence or the so-called third window (a small hole in the bony wall of the inner ear bone that can cause dizziness and hearing loss). In addition, the technology uses half the radiation dose, a new study shows.

The study, conducted in Bruges, Belgium, included 21 patients who had both a cone beam CT and a multidetector CT examination of their right and left temporal bones, said David Volders, MD, one of the authors of the study.

Two radiologists reviewed the images from both exams and scored them based on image quality and the presence of pathology. The study found that cone beam CT “corrected a false positive diagnosis for superior semicircular canal dehiscence in 11 out of 16 cases which were positive on multidetector CT (68.8%),” said Volders. Multidetector CT had indicated there was a dehiscence of the superior semicircular canal, when there wasn’t, he added. Cone beam CT also scored significantly better than multidetector CT in visualizing normal temporal bone anatomy.

“In our facility, all patients who undergo temporal bone imaging to diagnose fractures, congenital middle ear deformities, chronic ear infections, and conductive hearing loss are now scanned with cone beam CT,” said Volders in the press release. “The significantly better image quality and the very low radiation dose have made cone beam CT our main choice for temporal bone imaging.”

While apparently more effective, cone beam CTs are uncommon in radiology centers, and Volders urged colleagues to monitor their development as they improve and can be utilized for more uses.

The study was presented May 2, 2012 at the American Roentgen Ray Society Annual Meeting in Vancouver, Canada.

SOURCE: American Roentgen Ray Society