RSNA 2005 

Abstract Archives of the RSNA, 2005


SSA16-01

Multiplanar CT of the Temporal Bone in Microtia: Anatomy and Measurements of the Middle Ear and Contents

Scientific Papers

Presented on November 27, 2005
Presented as part of SSA16: Pediatric (Neuroradiology)

Participants

Daniel Martin, Presenter: Nothing to Disclose
Susan I. Blaser MD, Abstract Co-Author: Nothing to Disclose
Blake Papsin, Abstract Co-Author: Nothing to Disclose

PURPOSE

Microtia and external auditory canal dysplasias are not uncommon. Radiographic interpretation is complicated by a lack of understanding anatomy. Inadequate description of radiographic findings provides surgeons suboptimal information for surgical planning. Some radiographic features should be evaluated consistently to predict the potential for restorative surgical therapy. Surgical therapy includes: removal of bony atresia plate, enlargement of the stenotic EAC to provide an aidable canal, reconstruction of the tympanic membrane, mobilization of ossicles and if reconstruction is not possible, placement of a bone-anchored hearing aid (BAHA).

METHOD AND MATERIALS

Cases were identified via a radiology report word search program. CT and 3D-CT reconstructions of 57 patients with external ear dysplasias at the Hospital for Sick Children, Toronto ON from 1999-2005 were retrospectively evaluated. Direct axial, direct coronal 1 mm images and 3D reconstructions were performed utilizing dose reduction techniques. Analysis and measurements of anomalies of pinna, EAC, middle ear, ossicles and inner ear structures were performed.

RESULTS

Measurements of the normal and abnormal EAC, the size of the tympanic ring/ membrane and of the mesotympanum, epitympanum and ossicles were performed. There was a significant difference between the measurements of normal, isolated microtia patients and those in whom the microtia was part of a syndrome. Additionally, through these measurements we have discovered that a common radiographic description, “lateral displacement of fused ossicles” should be more correctly described as lateral hypoplasia of the epitympanum with normally positioned ossicles.

CONCLUSION

Continued and improved understanding of anomalies that exist in microtic ears will aid in surgical planning and hopefully allow improved correlation of anomalies with potential for auditory reconstruction.

Cite This Abstract

Martin, D, Blaser, S, Papsin, B, Multiplanar CT of the Temporal Bone in Microtia: Anatomy and Measurements of the Middle Ear and Contents.  Radiological Society of North America 2005 Scientific Assembly and Annual Meeting, November 27 - December 2, 2005 ,Chicago IL. http://archive.rsna.org/2005/4419428.html