Radiographic morphology of normal ring apophyses in the immature cervical spine.

BACKGROUND: The ring apophyses of the cervical spine have a variable appearance that changes with age. The times at which they appear and fuse at each level are not fixed. In this study, we aim to detail normal ranges of appearance of these ossification centers for each age group. MATERIALS AND METHODS: One hundred and eighty patients under the age of 21 attending the Royal Stoke University Hospital for cervical spine radiographs were retrospectively identified. The presence or absence of ring apophyses at each cervical level and whether these had undergone fusion was reported, as were the thickness, length, and craniocaudal and anteroposterior distance of the apophysis from the vertebral body. The angulation of the apophysis relative to the endplate was also noted. RESULTS: The youngest patient in which apophyses were seen was aged 3, but apophyses were otherwise rarely seen before the age of 6. All apophyses were present from age 14, and the superior apophyses fused by the age of 18, although unfused inferior apophyses were still seen in the 20-year age group. It was observed that apophyses were rarely separated from the vertebral body by greater than 1 mm in craniocaudal distance (1%) or 2.5 mm in anteroposterior distance (2.6%) and the anterior apophysis was angulated towards the endplate in only 1% of cases. CONCLUSIONS: We have detailed the range of normal appearances of the ring apophyses of the developing cervical spine. Cervical spine apophyseal injury is thought to be rare, but knowledge of normative morphological features should help in this diagnosis.

Implementation of a split-bolus single-pass CT protocol at a UK major trauma centre to reduce excess radiation dose in trauma pan-CT.

AIM: To quantify the dose reduction and ensure that the use of a split-bolus protocol provided sufficient vascular enhancement. MATERIALS AND METHODS: Between 1 January 2014 and 31 May 2014, both split bolus and traditional two-phase scans were performed on a single CT scanner (SOMATOM Definition AS+, Siemens Healthcare) using a two-pump injector (Medrad Stellant). Both protocols used Siemens' proprietary tube current and tube voltage modulation techniques (CARE dose and CARE kV). The protocols were compared retrospectively to assess the dose-length product (DLP), aortic radiodensity at the level of the coeliac axis and radiodensity of the portal vein. RESULTS: There were 151 trauma CT examinations during this period. Seventy-eight used the split-bolus protocol. Seventy-one had traditional two-phase imaging. One patient was excluded as they were under the age of 18 years. The radiodensity measurements for the portal vein were significantly higher (p<0.001) in the split-bolus protocol. The mean aortic enhancement in both protocols exceeded 250 HU, although the traditional two-phase protocol gave greater arterial enhancement (p<0.001) than the split-bolus protocol. The split-bolus protocol had a significantly lower (p<0.001) DLP with 43.5% reduction in the mean DLP compared to the traditional protocol. CONCLUSION: Split-bolus CT imaging offers significant dose reduction for this relatively young population while retaining both arterial and venous enhancement.