The radiation dose, clinical and anatomical implications of erect lumbar spine radiography: A single centre pre-post...

Lumbar radiographs remain a common imaging examination despite strategies to reduce their use. Many authors have demonstrated benefits in changing from traditional supine and recumbent lateral projections to a prone and/or erect orientation. Despite evidence of clinical and radiation dose optimisation, widespread adoption of these strategies has stalled. This article describes the single-centre implementation and evaluation of erect PA and lateral projections.

This was an observational study pre- and post-implementation of an erect imaging protocol. Patient BMI, image field size, source image and source object distances and DAP were collected together with assessment of radiographic spinal alignment and disc space demonstration. Effective dose was calculated with organ specific doses.

76 (53.5%) patients were imaged in the supine AP and recumbent lateral position, 66 (46.5%) had erect PA and lateral radiographs. Despite the larger BMI of the erect cohort and similar field sizes, effective dose was lower in the PA position by an average of 20% (p < 0.05), however, no significant difference in lateral dose. Anatomical improvements were evident with greater visualisation of intervertebral disc spaces in the PA erect (t = -9.03; p < .001) and lateral (t = -10.298; p < .001) orientations. Erect PA radiographs demonstrated a leg length discrepancy in 47.0% (0.3-4.7 cm) and a scoliosis in 21.2% of cases, with a significant link between these findings (r (64) = 0.44; p < .001).

Erect lumbar spine radiography provides information on clinical outcomes not available with recumbent projections. The improvements in anatomical visualisation and radiation dose reduction supports the local change in practice.

- Erect imaging can reduce effective dose with an optimised acquisition protocol - additional pathological information can be revealed by the erect posture. - postural awareness is critical to interpret images accurately.