Inter-observer agreement of vertebral fracture assessment with dual-energy x-ray absorptiometry equipment

Arch Osteoporos. 2021 Dec 10;17(1):4. doi: 10.1007/s11657-021-01046-w.


Purpose: To investigate the time and effort needed to perform vertebral morphometry, as well as inter-observer agreement for identification of vertebral fractures on vertebral fracture assessment (VFA) images.

Methods: Ninety-six images were retrospectively selected, and three radiographers independently performed semi-automatic 6-point morphometry. Fractures were identified and graded using the Genant classification. Time needed to annotate each image was recorded, and reader fatigue was assessed using a modified Simulator Sickness Questionnaire (SSQ). Inter-observer agreement was assessed per-patient and per-vertebra for detecting fractures of all grades (grades 1-3) and for grade 2 and 3 fractures using the kappa statistic. Variability in measured vertebral height was evaluated using the intraclass correlation coefficient (ICC).

Results: Per-patient agreement was 0.59 for grades 1-3 fracture detection, and 0.65 for grades 2-3 only. Agreement for per-vertebra fracture classification was 0.92. Vertebral height measurements had an ICC of 0.96. Time needed to annotate VFA images ranged between 91 and 540 s, with a mean annotation time of 259 s. Mean SSQ scores were significantly lower at the start of a reading session (1.29; 95% CI: 0.81-1.77) compared to the end of a session (3.25; 95% CI: 2.60-3.90; p < 0.001).

Conclusion: Agreement for detection of patients with vertebral fractures was only moderate, and vertebral morphometry requires substantial time investment. This indicates that there is a potential benefit for automating VFA, both in improving inter-observer agreement and in decreasing reading time and burden on readers.

Keywords: Dual-energy x-ray absorptiometry; Inter-observer agreement; Osteoporosis; Vertebral fracture assessment; Vertebral morphometry.

MeSH terms

  • Absorptiometry, Photon
  • Humans
  • Lumbar Vertebrae / injuries
  • Observer Variation
  • Retrospective Studies
  • Spinal Fractures* / diagnostic imaging
  • Thoracic Vertebrae