Nishchint Jain MBBS, Presenter: Nothing to Disclose

Suryanarayanan Bhaskar MS, MChir, Abstract Co-Author: Nothing to Disclose

To review embryogenesis and various abnormalities of the odontiod process. To discuss with images CT and MRI imaging features of odontoid abnormalities.

Odontoid process of axis acts as the central pivot of craniovertebral junction(CVJ).It develops from 1st and 2nd cervical sclerotome by enchondrial ossification.A myriad of congenital and acquired anomalies may affect odontoid process which present with varying signs and symptoms.Congenital anomalies include aplasia/hypoplasia ,disturbance of odontoid synchondrosis (os odontoideum and os terminale),os avis,bifid dens.Acquired odontoid lesions include trauma, infections (tuberculosis), inflammatory conditions (Rheumatoid arthritis, JRA,Reiters syndrome,ankylosing spondylitis) and tumours (osteoblastoma,eosinophilic granuloma, GCT,metastasis and neurofibromas).The various parameters assessed on CT and MRI to characterise these  anomalies are Odontoid morphology, topographical relation of odontoid tip to basion and anterior arch of atlas, CVJ craniometry for assessment of coexisting CVJ abnormalities, spinal cord status,predental soft tissue,ligamentous morphology,vertebral artery course and calibre and atlanto axial stability with dynamic MRI.

MRI and CT are essential tools in characterisation of odontoid abnormalities and thus facilitate accurate diagnosis and management.

Jain, N, Bhaskar, S, MRI and CT Imaging Spectrum of Odontoid Abnormalities: Pictorial Essay.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13022901.html