A workflow tool for measurements of vertebral heights on lateral spine radiographs based on automated placements of 6 points per vertebra was evaluated. The tool helps to standardize point placement among operators. Its success rate is very good in normal vertebrae but lower in vertebrae with more severe fractures. Manual corrections were required in 192 of 1257 analyzed vertebrae.
Introduction: To evaluate a new workflow tool (SA) for the automated measurements of vertebral heights on lateral spine radiographs.
Methodology: Lateral radiographs from 200 postmenopausal women were evaluated at two visits. Genant's semi-quantitative fracture assessment (SQ) and manual quantitative morphometry (QM) results were available from prior analyses. Vertebral heights from point placements using SA were compared with manual 6-point placement QM. Differences were quantified as RMS coefficient of variations (rmsCV) and standard deviations (rmsSD).
Results and conclusions: SA required manual corrections in 192 of 1257 vertebrae. SA heights were larger than QM ones by 2.2-3.6%. Correlations (r2 > 0.92) between SA and QM were very high. Differences between QM and SA were higher for fractured (SQ = 2; rmsCV% 14.5%) than for unfractured vertebrae (rmsCV% 4.2-4.7%). rmsCV% for QM varied between 3 and 6% and for SA between 2.5 and 7.5%. For SA, highest rmsCV% was obtained for T4 and L4. Manual correction mostly affected the end vertebrae T4 and L4. SA helps to standardize point placement among operators. The algorithm success rate is very good in normal vertebrae but lower in vertebrae with more severe fractures, which are of greater clinical interest but are more readily recognized without morphometric measurements.
Keywords: Active shape and appearance models; Automated quantitative morphometry; Vertebral fracture.