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E1945. Evaluation of the Craniocervical Junction From Birth to 2 Months of Age: Normal Values on CT
Authors
  1. Ritu Bordia; Saint Louis University
  2. Marshall Meeks; Saint Louis University
Objective:
The purpose of our study was to determine normal range of measurements for craniocervical junction (CCJ) relationships in infants from birth to age 2 months on CT examinations.

Materials and Methods:
A list of all neurological CT examinations performed in children from birth to 8 weeks of age at our children’s hospital from January 2013 to Oct 2019 were reviewed using radiology report-search software. Inclusion criteria included CT examinations performed in a child <= 60 days old, field of view including skull base to at least C4, and multiplanar reconstructed images available in PACS. By institution protocol, these studies included CT cervical spine, CT facial bones, CT paranasal sinus, CT neck soft tissues and CT angiograms of the neck. Exclusion criteria included clear imaging evidence of CCJ injury or developmental anomaly. Examinations degraded by significant motion artifact through the area of interest were also excluded. The following commonly used parameters for CCJ evaluation were used (1)- basion–axial interval (BAI), basion–dens interval (BDI), Powers ratio, atlantodental interval (ADI), and atlantooccipital interval (AOI). All measurements were performed by 2 reviewers independently on PACS without using magnification.

Results:
54 studies were identified from the report search. 34 studies met the inclusion criteria. The male to female ratio was 21:13. Patient age range was from 0 days to 8 weeks. The BAI ranged from -2 to 3.6 mm. The BDI ranged from 3-8.9 mm (mean - 6.3 mm) and AOI ranged from 0.6- 2.6 mm (mean 1.5 mm). The ADI could be measured in 13 studies and ranged from 0.7-3.4 mm (mean 2.1 mm).

Conclusion:
CCJ injuries are difficult to evaluate, particularly in very young infants. This population is vulnerable to CCJ injuries due to inherent anatomical characteristics and from non-accidental trauma mechanisms (2). The incidence of cervical spine injury is likely underestimated in cases of NAT (3). This is partly due to the inherent limitations of the commonly used modalities, radiographs and CT, differences in anatomy from adult spine and presence of normal variants. Many of us interpreting radiologists are less experienced in the evaluation of neonatal craniocervical junction since cervical spine is imaged very infrequently in neonates. We propose that the measurements of normal CCJ relationships from this study can be used as reference measurements in neonates and improve radiologists’ confidence in detection of CCJ in this population.