Supine vs decubitus lateral patient positioning in vertebral fracture assessment.
In vertebral fracture assessment (VFA), lateral scans are obtained with the patient positioned supine (C-arm densitometers) or lateral decubitus (fixed-arm densitometers). We aimed to determine the impact of positioning on image quality and fracture definition. We performed supine and decubitus lateral VFA in 50 postmenopausal women and used the algorithm-based qualitative method to identify vertebral fractures. We compared the 2 techniques for the identification of fractures (kappa analysis) and compared the numbers of unreadable vertebrae (indiscernible endplates) and vertebrae that were projected obliquely (Wilcoxon matched-pairs signed-rank test). The kappa score for agreement between the VFA techniques (to identify women with vertebral fractures) was 0.84 (95% confidence interval [CI]: 0.68-0.99), and for agreement with fracture assessments made from radiographs, kappa was 0.76 (95% CI: 0.57-0.94) for both supine and decubitus lateral VFA. There were more unreadable vertebrae with supine lateral (48 vertebrae in supine lateral compared with 14 in decubitus lateral; p=0.001), but oblique projection was less common (93 vertebrae compared with 145 in decubitus lateral; p=0.002). We conclude that there were significantly different projection effects with supine and decubitus lateral VFA, but these differences did not influence the identification of vertebral fractures in our study sample.
Sheffield NIHR Bone Biomedical Research Unit, Centre for Biomedical Research, Northern General Hospital, Sheffield, United Kingdom. Electronic address: m.a.paggiosi@sheffield.ac.uk.
Margaret Anne
MA
Paggiosi
Sheffield NIHR Bone Biomedical Research Unit, Centre for Biomedical Research, Northern General Hospital, Sheffield, United Kingdom.
Judith
J
Finigan
Sheffield NIHR Bone Biomedical Research Unit, Centre for Biomedical Research, Northern General Hospital, Sheffield, United Kingdom.
Nicola
N
Peel
Sheffield NIHR Bone Biomedical Research Unit, Centre for Biomedical Research, Northern General Hospital, Sheffield, United Kingdom.
Richard
R
Eastell
Sheffield NIHR Bone Biomedical Research Unit, Centre for Biomedical Research, Northern General Hospital, Sheffield, United Kingdom.
Lynne
L
Ferrar
D015502:Absorptiometry, Photon / Q000379:methods*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000293:injuries*; D008875:Middle Aged; D015663:Osteoporosis, Postmenopausal / Q000150:complications* / Q000000981:diagnostic imaging; D056888:Patient Positioning; D012189:Retrospective Studies; D016103:Spinal Fractures / Q000000981:diagnostic imaging* / Q000209:etiology; D013997:Time Factors; D055815:Young Adult