Computed Tomography of Paediatric Atlanto-axial Rotatory Subluxation: The Multiple Image Addition Method

K Wang, TKL Loke

Hong Kong J Radiol 2001;4:209-12

Paediatric atlanto-axial rotatory subluxation is an uncommon condition which may be catastrophic, even after minor trauma, if it is not recognised promptly. Many imaging methods may be used to diagnose the condition, but there is still no consensus as to which is the best method for definitive diagnosis and for the assessment of treatment outcomes. Plain cervical radiography and computed tomography of the cervical spine with three-dimensional reconstruction, are currently the most accepted methods.

Multiple contiguous axial computed tomographic images of the cervical spine, compressed into a single image by multiple image addition have been utilised by the authors in radiological assessment of paediatric atlanto-axial rotatory subluxation. The authors report this technique to be an easy and accurate method for both the diagnosis and assessment of treatment. This reconstruction method is less time-consuming than three-dimensional reconstruction. In addition, the summated axial images follow the diagrammatic classification described by Fielding and Hawkins, facilitating interpretation and accurate assessment during follow-up.