Widening of the basion dens interval is an important sign of cranioverterbral junction injury. Society for pediatric radiology 1999.
Midsagittal mdct images of craniocervical junction show basion dens interval as distance from most inferior portion of basion to closest point of superior aspect of dens.
Basion dens interval pediatrics radiology. The distance between the basion and the tip of the odontoid process should be 12 mm or less. The current literature on basion dens interval in children is sparse and based on bony measurements with variable values. In 97 5 of patients the basion dens interval was less than 10 5 mm compared with 12 mm based on data from radiographs.
The basion dens interval bdi is the distance between the basion and the tip of the dens used in the diagnosis of atlanto occipital dissociation injuries. The classification of these injuries is based upon the displacement of the occiput. Atlas dens interval adi in children.
The basion axial interval was difficult to reproduce on mdct images. It is the distance in mm between the basion and the superior extension of the posterior cortical margin of the body of the axis in the median midsagittal plane. Society for pediatric radiology 1999.
The distance from the basion to the posterior axial line basion axis interval and the distance from the basion to the tip of the dens basion dens interval should each be less than 12 mm figure 2. Vachhrajani s et al 2014. Harris et al 2 calculated that 95 of adults in their study population had a bdi and bai less than 12 mm and considered this value as the upper limit of normal.
The basion axial interval bai is the horizontal distance between the basion and the posterior cortex of the axis used in the diagnosis of atlanto occipital dissociation injuries. 2 9 0 5 3 9. Our goal was to establish the normal values of a recently described new imaging parameter the basion cartilaginous dens interval in children.
Separating the patient population into those in whom the os terminale was ossified and those in whom it was not revealed a difference of 2 mm in the upper limit of normal 9 5 and 11 6 mm respectively. An increase in this distance indicates instability. 4 4 0 4 5 4.
Vachhrajani s et al 2014. 5 year old boy without ossification of os terminale and normal basion dens interval measuring 10 mm. The method used by this group included the basion dens interval bdi originally described by wholey et al 4 as well as the basion axial interval bai.
2a basion dens interval bdi. Estimation of normal computed tomography measurements for the upper cervical spine in the pediatric age group. It is the distance from the most inferior portion of the basion to the closest point of the superior aspect of the dens in the median midsagittal plane.
Estimation of normal computed tomography measurements for the upper cervical spine in the pediatric age group j neurosurg.